Flight Test: Xtreme De­cathlon

One up from the Su­per De­cathlon, the Xtreme is not only fun for aer­o­bat­ics but a great all-round sports air­craft

Pilot - - CONTENTS - Words Nick Bloom Photos Keith Wil­son

Ahigh-wing aero­plane per­form­ing aer­o­bat­ics looks some­how in­ap­pro­pri­ate, a bit like a fat man danc­ing. How­ever, there’s no rea­son why an aer­o­batic ma­chine shouldn’t have a high wing, par­tic­u­larly if it has a trans­par­ent roof in the cabin. Per­son­ally I rather like to sit un­der the wing, be­cause it gives you an un­in­ter­rupted view down­wards when you’re not fly­ing aeros. A high-winger with tan­dem seat­ing (exit the side-by-side Cessna Aer­o­bat) short wing­span, 210hp and a CS prop is even bet­ter−a fat ath­lete danc­ing. En­ter the Xtreme De­cathlon. A fly­ing club think­ing of ac­quir­ing a 200hp Ex­tra or a used Slingsby T67 might want to con­sider one of these high-wing aero­planes in­stead. And if you’re a pi­lot think­ing of tak­ing up aer­o­bat­ics, you might wonder how an Xtreme De­cathlon com­pares with the other op­tions−in par­tic­u­lar, whether it might get you onto the winner’s podium in Stan­dard and In­ter­me­di­ate com­pe­ti­tions.

For a short spell in 1960s Amer­ica the Citabria (‘Air­batic’ back­wards) was the only af­ford­able air­craft cer­ti­fied for aer­o­bat­ics. A spe­cially-strength­ened vari­ant on the Cub-like Aeronca Cham­pion, the Citabria im­planted it­self into the Amer­i­can psy­che just as the Piper Cub did for pri­mary train­ing and low-and­slow, af­ford­able fly­ing. Over the decades a steadily age­ing group of pi­lots harked back to their youth when they wanted some­thing in which to fly the oc­ca­sional loop and roll. “I want one of them Citabrias,” they said. Only what they ac­tu­ally wanted was a Citabria that was brought up to date with a mod­ern en­gine, more horse­power and more per­for­mance. (“Got me more dol­lars now.”) The De­cathlon was the re­sult−ef­fec­tively a souped-up Citabria with a semisym­met­ri­cal wing section. As the trend to ever-bet­ter per­for­mance con­tin­ued, the

Su­per De­cathlon fol­lowed and now we have the Xtreme De­cathlon.

I’m not nor­mally a fan of tak­ing a good for­mula and adding power, be­cause with power comes weight. A heav­ier en­gine is also thirstier, so big­ger fuel tanks are needed, and then you need to beef up the air­frame to cope. A heav­ier air­frame needs more power, so you can get into a vi­cious cir­cle. In aer­o­bat­ics, light air­frames make for smaller, tighter loops that don’t go on for so long. But there is a limit to what an air­craft like the Citabria, with lots of wing area and not much power (early mod­els had 100hp) can do. It’s been a while since I flew one, but I doubt whether it will man­age even a quar­ter ver­ti­cal roll. You need power for those ver­ti­cal ma­noeu­vres. Also, in dis­play fly­ing you need power to main­tain height. Power gives you the abil­ity to be­gin low, where the crowd can see you, and stay in front of them mak­ing a loud noise.

So my key ques­tions for the Xtreme De­cathlon are: one - will it make a good dis­play air­craft? Two - will all that weight and power have made it un­pleas­ant to fly? And three - will it man­age a ver­ti­cal roll?

The Xtreme De­cathlon that is the sub­ject of this flight test be­longs to ex-aerostars pi­lot and air­line owner Gene Will­son and his son Pa­trick, who is 24 and works at Stansted as an air­craft en­gi­neer. It’s based at Audley End and has an N-registration. Fly­ing along­side us will be eightysome­thing ex-air­line pi­lot Digby with cam­era­man Keith Wil­son in a Cessna 172 from Anglian Flight Cen­tre.

Pa­trick will be tak­ing the rear seat in the Xtreme De­cathlon and I will be in the des­ig­nated solo pi­lot po­si­tion−the front. He tells me he has more or less learned to fly on the Xtreme, mean­while mas­ter­ing tail­wheel fly­ing. Now, with 115 hours power, plus a few on glid­ers, he is learn­ing to fly aer­o­bat­ics in it. The Xtreme De­cathlon has en­abled him to do all this with a sin­gle aero­plane. Plus it has the

po­ten­tial for him to fly air­shows in a two-ship, fa­ther-and-son for­ma­tion act with Dad in the Xtremeair XA42. Both air­craft are in the colours of Ti­tan Air­ways, the char­ter air­line owned by Gene.

PPL train­ing in the Xtreme De­cathlon makes sense, be­cause de­spite the clipped wings (31ft as against the Champ’s 35ft), pow­er­ful con­trols and big­ger en­gine (210hp as against 65), it is still at heart a Cham­pion, which was de­signed to be a ba­sic trainer. And the De­cathlon has long been the club aer­o­batic trainer of choice in Amer­ica. I was told a few years ago by oc­ca­sional Pi­lot con­trib­u­tor Don Peter­son that in his home state of Texas (where the air­fields are hot ’n’ high) they oc­ca­sion­ally run Sports­man aer­o­bat­ics con­tests with a sin­gle De­cathlon: contestants take it in turn to fly the se­quence two-up, with the in­struc­tor in the back seat. That places a lot of de­mands on the aero­plane (not to men­tion on the in­struc­tor), and says a lot about its in­her­ent strength.

I be­gin with a quick walk around the air­craft. It’s 1940s tech­nol­ogy−welded steel tube fuse­lage and tail sur­faces, the wings with alu­minium spars, in­ter­nal brac­ing wires and ribs cut and bent from sheet alu­minium, and alu­minium sheet over the wing lead­ing edges−all cov­ered in dacron fab­ric, stitched-on, heat-shrunk, taped and cov­ered in a paint that (to­day’s tech­nol­ogy) fills the weave and ends up look­ing like plas­tic film. The wing spars are se­cured to the top of the cabin by a sin­gle bolt each side−ef­fec­tively a hinge−and braced by two lift struts, stiff­ened by jury struts mid-span.

Wittman spring legs carry the main­wheels, which are fit­ted with toe-op­er­ated hy­draulic disc brakes, and the steer­able leaf-sprung tail­wheel is linked to the rud­der with coil springs. There are han­dles at the back of the fuse­lage for lift­ing the tail; I try and can’t quite lift it. Amer­i­cans seem­ingly are ob­sessed with pro­tect­ing the pro­pel­lers of their tail­wheel air­craft and set the main wheels fur­ther for­ward than in most Euro­pean de­signs, and the Xtreme De­cathlon is no ex­cep­tion. There is a penalty to hav­ing the main wheels fur­ther away from the cen­tre of grav­ity−it takes longer to lift the tail at take­off (so you start blind), there’s a greater propen­sity to ground­loop, and it makes it harder to land tail-high.

The ailerons are in­ter­est­ing−they have a neat pushrod in­board to the up­per

It’s 1940s tech­nol­ogy — welded steel tube fuse­lage and tail sur­faces... wings with alu­minium spars... cov­ered in dacron fab­ric

sur­face, and bulge no­tice­ably out­side the section of the wing, pre­sum­ably for in­creased power and per­haps to counter ad­verse yaw. They are not dif­fer­en­tial, go­ing down by the same de­flec­tion as up.

This be­ing es­sen­tially a no-frills aero­plane, there are no flaps and only one set of in­stru­ments−the rear seat oc­cu­pant has to peer over the shoul­ders of the per­son in front (not that there aren’t frills, no­tably the wheel spats). There is space for 100lb of lug­gage be­hind the rear seat. The ‘built to a cost’ theme is per­haps most no­tice­able in the flat section of the ver­ti­cal tail sur­faces and their ex­ter­nal wire brac­ing; few man­u­fac­tur­ers build tails like that these days. Forty gal­lons (US) of fuel is plac­arded, and it’s held in two twen­ty­gal­lon wing tanks. There are cold and hot air vents on the fuse­lage walls un­der the in­stru­ment panel and a park­ing brake. Fuel and oil sys­tems al­low in­verted flight.

As op­posed to the Cub, the Champ and its de­scen­dants have a high-sided cabin and a rel­a­tively short rear fuse­lage, giv­ing the Xtreme a slightly dumpy look. The door on the right-hand-side swings for­ward and locks and you climb in via a step below the lower longeron, with plenty of struts in the fuse­lage avail­able as hand­holds. The seats are bolted-to-the floor and of the ‘throne’ kind−i.e. up­right, and there are sin­gle, aer­o­batic-style five-point har­nesses for each oc­cu­pant. El­e­va­tor trim is man­ual, on the left wall, the throt­tle lever is above it and, be­tween the two, there’s an al­ter­nate air lever. The con­trol sticks have two curves built into them−very grace­ful.

I hoist my­self up and try the seat, which seems to be ad­e­quately high and close to the rud­der ped­als. I have short legs and some­one with longer ones would just have their knees a bit higher. (The front seat is ad­justable.) My first feel­ing is plea­sure, be­cause the cock­pit is enor­mous and has lots of clear Per­spex and room. Pa­trick sits be­hind me and I close the door, which has two ex­tra safety catches as well as the han­dle. And there’s an emer­gency door re­lease, a fire ex­tin­guisher and other ‘Fed’ safety requirements man­dated in US cer­ti­fi­ca­tion. There’s a win­dow on the left side, op­po­site the door, which you can open in flight up to 130mph.

Twist­ing around to op­er­ate switches

Time to go, so I run through the start-up pro­ce­dure, di­rected by Pa­trick. This in­volves twist­ing around to op­er­ate switches on the left wing root and even­tu­ally push­ing the starter but­ton on the in­stru­ment panel. The en­gine is still warm from taxy­ing to the pumps and starts on the third try in lean. I push the plunger to rich and it set­tles down. We don our noise-sup­press­ing head­sets−a must in this noisy boom-box with 210hp up ahead−and I do my best to get to grips with the glass panel tech­nol­ogy in front of me. This (ex­cuse me while I con­sult my notes) com­prises an EDM-930 for the en­gine, a GTN 650 Garmin GPS nav­comm unit and an Evo­lu­tion 1000 EFIS−BUT there are ana­logue flight in­stru­ments for a di­nosaur like me. Pa­trick tells me− and I believe him− that he finds it eas­ier to work from the Evo­lu­tion 1000. While I taxi from the pumps to join the C172, Pa­trick di­rects my fum­bling at­tempts to change fre­quency on the Garmin’s touch­screen.

Taxy­ing is dead easy with the steer­able tail­wheel and toe brakes, although this vari­ant on the De­cathlon had per­force to be fit­ted with longer legs to main­tain prop clear­ance, so even from the front seat I have to taxi in a se­ries of S-turns, as I can’t see over the nose.

We reach the C172, make ra­dio con­tact, taxi out, run through our pre­flight checks−which for us are cy­cling the prop, ‘full and free con­trols’, mag checks and slow run­ning−and tell Digby we’re ready. The 172 lum­bers down the run­way. I wait un­til its wheels are just clear of the grass then open the throt­tle smoothly all the way for­wards, ap­ply­ing rud­der to counter spi­ral air­flow from the prop−at this point the rud­der is light. The ac­cel­er­a­tion is im­pres­sive, but with stick fully for­wards it still takes three sec­onds be­fore the tail lifts and I can see over the nose. The main legs (alu­minium) have a fair bit of springi­ness, and give and flex rather more than is com­fort­able over Audley End’s some­what un­du­lat­ing run­way. It’s a bouncy ride. Also I sense there’s a rather high wing load­ing and although we gather speed quickly, we’re half way down the run­way be­fore I feel con­fi­dent about lift­ing off. In­evitably we are now catch­ing up the 172, so I have to throt­tle back and raise the nose to keep a safe dis­tance. This can feel awk­ward in some air­craft−we are only 100ft above the trees−but the Xtreme

De­cathlon seems happy enough and soon I am able to add power and draw slowly to­wards the 172. Pa­trick asks me to back off the pro­pel­ler rpm, so I pull the blue plunger out a frac­tion. First im­pres­sions are that this is a good for­ma­tion air­craft with lots of con­trol au­thor­ity, easy to po­si­tion as re­quired by Keith, and with few blind spots to keep­ing the Cessna in view. The ailerons are light and sen­si­tive, the el­e­va­tor less so, and the rud­der a tri­fle heavy, so con­trol har­mony is tra­di­tional, although per­haps not ideal for aer­o­bat­ics. We go through the usual pho­to­shoot rou­tine− turns one way then the other, a head-on shot with full sideslip and then a break­away, banking the Xtreme steeply to show its belly. The only sur­prise is dur­ing the sideslip ma­noeu­vre for the head-on shot: de­spite my fully open­ing the throt­tle, the Cessna is draw­ing away. I call on the ra­dio for Digby to throt­tle back a lit­tle, which he does and af­ter that we can draw in close so that Keith can get his lens filled with Xtreme De­cathlon and strain­ing Bloom. The fi­nal ma­noeu­vre calls for me to take the lead with Digby for­mat­ing on us from be­hind, so that I can roll in­verted for a photo of the air­craft up­side-down. I open the throt­tle (too much as it turns out) for some com­pen­sat­ing power. A touch of right rud­der at knife edge keeps the nose up, and then, fore­warned by Pa­trick, I give a lot of for­ward stick and get the nose higher than one would ex­pect. Un­der the neg­a­tive G, my base­ball hat and head­set lev­i­tate off my head and as­cend to the roof, leav­ing me with no means of com­mu­ni­ca­tion and no ear de­fence. It’s pretty noisy. I sus­tain in­verted for a slow count of twenty−hope­fully long enough for Digby to draw along­side and Keith to close the cam­era shut­ter−take a quick, be­lated look at the ASI and am star­tled to see the air­speed has risen to 120mph. We had agreed on a for­ma­tion speed of 95. We haven’t been in a dive, it’s that ex­tra power, which has speeded us up to a rather sur­pris­ing de­gree; clearly this air­craft doesn’t come over all draggy when up­side-down. I swing the stick left, with left rud­der, and we roll up­right. I look over my right shoul­der and there’s the 172, so it seems the ma­noeu­vre was a suc­cess.

Pa­trick has re­trieved my head­set and passes it to me, to­gether with my base­ball hat. Keith calls on the ra­dio to say he’s got all his photos and the Cessna heads back to Audley End. Pa­trick of­fers to ad­just my head­set−“i’ve never had it come off,” he says. “Maybe it’s your hat!” It does seem more se­cure, ad­justed and mi­nus hat.

First aer­o­batic ma­noeu­vre

The first aer­o­batic ma­noeu­vre I at­tempt is a loop. I ex­pect the Xtreme De­cathlon to be one of those air­craft with a high wing load­ing that likes plenty of speed, so I dive to 130mph be­fore be­gin­ning the pullup. I haul back on the stick quite lustily but not lustily enough, and the aero­plane makes a big loop. My pull on the re­cov­ery is also short of what is ev­i­dently re­quired, so we lose height. That el­e­va­tor re­ally is heavy at aer­o­batic speed. Af­ter climb­ing and repo­si­tion­ing, I try again and make some­thing more nearly round−but I re­alise that I have an­other prob­lem, which is in­tro­duc­ing aileron dur­ing the loop. It’s partly, I can see, a re­sult of hav­ing the wings up there, so I have less hori­zon to line up on once the nose starts to rise. Also, no doubt, hav­ing a heavy el­e­va­tor and light ailerons makes it easy to in­tro­duce un­wanted roll in­puts while haul­ing back on the stick. My next try is bet­ter, but the com­bi­na­tion of lim­ited view, heavy el­e­va­tor and light ailerons does make ac­cu­rate loop­ing tricky.

Next I try stall turns. I sus­pect this is an air­craft where I will need to make rud­der ad­just­ments (to off­set spi­ral air­flow) dur­ing the pull-up, or I’ll ar­rive at the ver­ti­cal one wing low. So as I pull up, I turn my head to both sides al­ter­nately, try­ing to get the same pic­ture on the right and the left. This head­turn­ing, while pulling G and also try­ing to make sure the wings are level against the hori­zon (which you can only do while look­ing for­wards) is un­nat­u­ral. Gen­er­ally it’s only nec­es­sary when stall turn­ing in an un­fa­mil­iar air­craft; once you get used to it, you ap­ply the cor­rect amount of rud­der au­to­mat­i­cally. So then you only need to turn your head to one side (to see when the wing makes a right an­gle against the hori­zon). De­spite my best ef­forts, we hit the ver­ti­cal right wing low. At least we’ve plenty of power, haul­ing us ver­ti­cally up­wards as I ap­ply left rud­der to try and straighten up. I al­low this rather un­cer­tain and wob­bly as­cent to con­tinue for maybe three sec­onds, then kick in full left rud­der. The aero­plane piv­ots neatly and now we’re point­ing straight down. In­ter­est­ing−it could have rolled, slid back­wards or mis­be­haved in var­i­ous ways, but it didn’t. So the Xtreme De­cathlon is easy to stall turn.

I work on my ver­ti­cals for a while, try­ing to get the rud­der right, but also adding first a quar­ter-, then a half-roll while ver­ti­cal and be­fore stall-turn­ing. It helps a lot when I fi­nally start re­ally pulling on the stick to get to the ver­ti­cal; I’ve been squan­der­ing en­ergy on a huge quar­ter loop. How­ever, af­ter sev­eral tries−and there’s a limit to how long one can spend try­ing in a flight test−the most that I can man­age is a three-quar­ter roll. Which isn’t bad at all, and cer­tainly good enough for In­ter­me­di­ate level com­pe­ti­tions. Fur­ther­more, Pa­trick says the Xtreme per­forms no­tice­ably bet­ter with­out a pas­sen­ger. He thinks that, one-up, it will just man­age a full ver­ti­cal roll. This can per­haps be ex­ited with a half-loop (a ‘humpty bump’ in aer­o­batic par­lance) or stall turn, “But,” he sug­gests, “prob­a­bly not a fly-off” (i.e. pitch­ing for­wards into level flight).

Next I try some­thing which I sus­pect will be a lot eas­ier, a four-point hor­i­zon­tal roll (with hes­i­ta­tions at each quar­ter). This goes well, although the rud­der feels heavy in the last quar­ter. When I say ‘heavy’ I mean I have to push hard enough to make me fear­ful of get­ting cramp in my calf mus­cle.

Pa­trick has never ex­pe­ri­enced a rolling cir­cle and I am cu­ri­ous to know if I can still fly one (it’s been a while) so I try turn­ing through ninety de­grees while fly­ing a roll, co­or­di­nat­ing the two into one flow­ing ma­noeu­vre. It’s rough but I just about man­age it. This time the rud­der push re­quired is a lim­it­ing fac­tor: the ma­noeu­vre calls for more push and I can’t sum­mon enough mus­cle-power to de­liver it. It’s not the air­craft that’s the prob­lem; it’s me. The Xtreme De­cathlon is a bit of a brute. How­ever, so was my Sky­bolt, decades ago, which had sim­i­larly heavy el­e­va­tor and rud­der. So much so that to be­gin with I flew com­pe­ti­tions with both hands on the stick. How­ever, I soon adapted and af­ter a while the rud­der and el­e­va­tor no longer felt heavy; they felt right.

Next, I try a half re­v­erse Cuban, half-rolling on a 45-de­gree climb­ing line, then pulling through three-quar­ters of a down­ward loop to end in level flight. You can draw a long climb­ing line in this air­craft, since the half-roll is fast and the aero­plane will climb steeply for a long time

be­fore it runs out of en­ergy, so this is a pleas­ant ma­noeu­vre. I say ‘the half-roll is fast’, but in fact the roll rate de­pends on what you’re used to. By the stan­dards of a Pitts Spe­cial or an Ex­tra, it would feel painfully slow; against a Tiger Moth, light­ning-fast. I would say it’s above av­er­age for an aer­o­batic trainer, faster than a Chip­munk, Cessna Aer­o­bat or Stampe. Pa­trick says it’s 180 de­grees a sec­ond. So a slow count of two for a full roll.

The half Cuban I fly next (half-roll on the down­ward line) isn’t quite so pleas­ant, be­cause you re­ally do need to pull firmly at the end of a dive and I’m still not ac­cli­ma­tised to that. From an en­try speed of 130mph I try a half loop, half roll ‘Im­mel­man’ which earns a “Nice” from long-suf­fer­ing Pa­trick in the back. Some air­craft run out of puff and sink at the top, but not this one.

Sam­pling the spin be­hav­iour

Time to sam­ple the spin be­hav­iour. The aer­o­batic com­pe­ti­tion spin, which Pa­trick hasn’t ex­pe­ri­enced, re­quires a stalled en­try from level flight, so I set up straight-an­dlevel, then slowly close the throt­tle, pro­gres­sively rais­ing the nose so that we nei­ther climb nor de­scend, be­ing care­ful to keep the slip ball cen­tred. The stall warn­ing howl­ing in our ears is a dis­trac­tion (but the Feds will have in­sisted that the air­craft has one). The el­e­va­tor, so heavy at aer­o­batic speeds, be­comes pro­gres­sively lighter, so con­cen­tra­tion is re­quired. Whether it’s that, the fuel in the wing tanks be­ing out of bal­ance or the spi­ral air­flow from that big, heavy, wind­milling CS prop, when the aero­plane stalls it also drops its right wing. It’s a left-turn spin I have in mind, so I push in full left rud­der (light at this speed) and pull the stick all the way back. The aero­plane hes­i­tates, and when it does drop its nose and be­gin ro­ta­tion, it’s un­tidy. For a mo­ment it feels prop­erly stalled and then the wings grip the air and we’re in a spi­ral dive. I try that stall en­try a few more times and don’t suc­ceed in get­ting a proper com­pe­ti­tion spin. I think I know why: the C of G is too far for­wards. That is a com­mon prob­lem with aer­o­batic train­ers− the Feds (EASA and the CAA are the same), and some­times also the air­craft de­sign­ers, are so con­cerned with stu­dents in­ad­ver­tently get­ting into un­in­tended spins that they play it safe and then ‘add a bit more for luck’. It’s prob­a­bly the same think­ing that’s be­hind the rather heavy (at higher speeds) el­e­va­tor and rud­der.

Hav­ing said that, I am sure that with prac­tice and per­haps a bit of ‘cheat­ing’, the Xtreme De­cathlon could be made to pro­duce a high-scor­ing com­pe­ti­tion spin. The aero­plane has pow­er­ful con­trols, and that can off­set other fac­tors. I used to watch Mark Jef­feries get high scores for spins in his Bücker Jung­mann, which had a very for­ward C of G. He knew how to make it look to the judges as if the

aero­plane stalled, the nose dropped, and only af­ter that came (so it ap­peared) a fully-stalled au­toro­ta­tion. All done by sleight of hand.

In a turn­ing stall, un­sur­pris­ingly, the Xtreme De­cathlon goes for the safe op­tion, rolling level. I also try loi­ter­ing turns at half power and low speed and the only haz­ard is an in­sid­i­ous loss of height. This doesn’t strike me as the kind of aero­plane that will sud­denly flick into a rapid spin fol­low­ing low-and-slow abuse. If it does have a built-in risk fac­tor, it’s en­ter­ing a loop or bar­rel roll a lit­tle too near the ground, be­cause it has a mod­er­ately high wing-load­ing and, although the power is there to get you out of trou­ble, you have to see trou­ble com­ing and get the nose up and the power on in time. The wing load­ing of the Xtreme De­cathlon is 11.9lb/sq ft. For a Stampe it’s 8.9. On the other hand, for a Chip­munk it’s higher (12.8) and for a re­ally high per­for­mance ma­chine, like an Ex­tra 330L, 15.2. So the Xtreme De­cathlon’s wing load­ing isn’t by any means ex­ces­sive.

Next, given that we are near the weight limit for flick rolling, I try a low-strain vari­ant of the ma­noeu­vre, climb­ing at low power at 35 de­grees nose-up, un­til the speed falls to 65mph, then ap­ply­ing full left rud­der and back stick. The air­craft stalls and lazily ro­tates, drop­ping its nose. The ro­ta­tion is av­er­age−nei­ther fast nor slow−but it takes quite a hefty push on right rud­der to stop it. You end up in a slow-speed dive. Pa­trick’s not tried this (some­times called a ‘Pussy Flick’, be­cause it’s gen­tle on the air­frame) and has a go. Two tries and he’s got it. Next I try an Avalanche (flick roll at the top of a loop, which is also low-strain) and it’s tricky. Prob­a­bly be­cause the rud­der is heavy and I don’t push it firmly and quickly enough, the air­craft barely stalls. It be­gins to au­toro­tate and then that for­ward C of G makes it­self felt and the ro­ta­tion de­gen­er­ates into a spi­ral dive. Messy. I also try a level stall, hold­ing the stick all the way back in­stead of re­cov­er­ing. This pro­duces a dra­matic height loss in a com­pletely-con­trol­lable mush down­wards. We al­ter­nate be­tween swoop­ing up­wards and div­ing. As­ton­ish­ingly, the ailerons con­tinue to work nor­mally when­ever a wing drops, even in this con­fig­u­ra­tion. Very for­giv­ing.

Aer­o­batic ca­pa­bil­ity an­a­lysed

That’s the end of the aer­o­bat­ics as­sess­ment. It’s per­haps a bit rash to draw con­clu­sions on such a brief ac­quain­tance, but I would think that the Xtreme De­cathlon is po­ten­tially ca­pa­ble of all the ma­noeu­vres in the In­ter­me­di­ate com­pe­ti­tion syl­labus. It’s prob­a­bly a rather bet­ter trainer than the Ex­tra at Stan­dard and In­ter­me­di­ate level. Its lack of aero­dy­namic so­phis­ti­ca­tion means, for in­stance, that although the roll rate is rapid enough to get away with just shov­ing the stick over, to get a good score, you will have to co­or­di­nate rud­der and el­e­va­tor prop­erly through­out the roll−and that’s a good les­son. On the debit side, for Stan­dard level aer­o­bat­ics, the spin might be tricky to mas­ter; it’s a high-scor­ing ma­noeu­vre at Stan­dard, and im­por­tant. On the credit side, the aero­plane is quite large and easy to judge and has plenty of per­for­mance, so main­tain­ing height shouldn’t be a prob­lem, both in con­tests and in dis­plays. The trick will be to keep the speed up, same as with a Pitts.

Is it pleas­ant to fly? Not es­pe­cially for me at this junc­ture, but then the aero­plane I fly aer­o­bat­ics in ev­ery week is a low­power, light, sin­gle-seat bi­plane with low con­trol forces. I think were I to fly the Xtreme De­cathlon a few more times, I’d find it just as pleas­ant as my Cur­rie Su­per Wot. There is (apart from the pas­sen­ger seat), though, one huge ad­van­tage over the Wot, which I am now about to sam­ple. In cruise, the poor old Wot can only man­age 85mph and has a cramped cock­pit. The space I’m sit­ting in is much big­ger.

On the jour­ney back to Audley End, I start off at 120mph, which feels com­fort­able, then throt­tle back to 110 af­ter dis­cov­er­ing from Pa­trick that that’s what

he and his dad nor­mally cruise at. The ‘book’ fig­ure is much higher: 149mph.

This air­craft gives a smooth ride. You can make turns on stick alone, although some rud­der is re­quired for steeper turns. The aero­plane is also rea­son­ably sta­ble and will fly hands-off for a while be­fore one wing lazily de­scends. The el­e­va­tor trim is a lit­tle on the sen­si­tive side but works fine. I try steer­ing with rud­der and it doesn’t re­ally work−the air­craft banks even­tu­ally and starts to turn, but by then the nose has dropped and the speed is ris­ing.

Pa­trick di­rects me back to Audley End, but the air­field seems to be in­vis­i­ble and it’s only when he takes con­trol and lines me up with the run­way that I fi­nally see it. He sug­gests an ap­proach of 80mph to­day, “as it’s windy. You can ap­proach at seventy for a shorter land­ing”. Audley End House is in the way and there are strict in­struc­tions not to over­fly it. I take the dif­fi­cult route, a close-in right base, and the strong cross­wind and tur­bu­lence re­sult­ing from sun and scat­tered cloud, tall trees and a hilly ap­proach do make it rather chal­leng­ing.

It doesn’t help that I’m com­ing in fairly low; I’d have done bet­ter to come in high over the ob­sta­cles and sideslip once we’re over the air­field bound­ary. As it is, the aero­plane is buck­eted about like a dinghy in a rough sea un­til we’re over the thresh­old. Once I am able to close the throt­tle and the ground lev­els out, our pas­sage be­comes less bumpy. El­e­va­tor is def­i­nitely sen­si­tive and we waft up and down as the air­craft be­gins to slow. Just when I think it’s go­ing to drop on, it floats up­wards. Think­ing, surely we must be close to the stall by now, I open the throt­tle a tad to cush­ion the land­ing. The Xtreme De­cathlon drops on and that springy un­der­car­riage makes it­self felt, but the aero­plane has lit­tle en­ergy and with some firm brak­ing, it soon slows. One ad­van­tage of that for­ward-set un­der­car­riage: you can brake firmly with­out fear of dam­ag­ing the prop.

We’ve landed in about a third of the run­way, but know­ing Audley End’s pe­cu­liar­i­ties (trees at the far end), I elect to back­track rather than make this a touch and go. My sec­ond take­off is like the first−rather pro­longed, but per­fectly okay. With prac­tice I could prob­a­bly leave the ground safely in a still wind in 250 me­tres. Ini­tial climb rate is a healthy 1,500fpm (and you don’t need a lot of rud­der dur­ing the climb). How­ever, this isn’t quite a STOL ma­chine.

My sec­ond land­ing is off a higher ap­proach, us­ing sideslip and com­ing in with Audley End House on the easy side−my right. The view on fi­nal was man­age­able with­out sideslip in my last ap­proach but, as you would ex­pect, vastly bet­ter with the nose canted off to one side. The Xtreme De­cathlon lands a lit­tle more smoothly but−would you believe−it does that last minute waft up­wards again. So I hand over to Pa­trick to fly a cir­cuit. I’m watch­ing his land­ing and I’m pretty sure it wafts up­wards for him too. My penul­ti­mate land­ing is an at­tempt to wheel on, rather than three-point, but I touch down a lit­tle too fast and the sen­si­tive el­e­va­tor and springy un­der­car­riage de­feat me. The aero­plane bounces a few times and ob­vi­ously isn’t go­ing to set­tle down, so I open the throt­tle, lift off and land on three points fur­ther into the run­way. By now I feel that I’m get­ting the mea­sure of the aero­plane, so I make one last, tight cir­cuit and fi­nally achieve a smooth land­ing. This time I’m ready for the last mo­ment ‘waft’ and cush­ion it with just the right amount of throt­tle. As we taxi in, Pa­trick says he spent a day at an­other air­field try­ing to wheel on the Xtreme De­cathlon, even­tu­ally man­ag­ing to do it, “but it wasn’t easy and I prob­a­bly won’t wheel it on again”.

Ca­pa­ble, flex­i­ble and well priced

So, to an­swer the three ques­tions I set my­self at the be­gin­ning: yes, it has the per­for­mance and roll rate to make a good dis­play air­craft. Sec­ond, added weight and power have not had too much ad­verse ef­fect on fly­ing qual­i­ties and ob­vi­ously have done a lot to min­imise height loss dur­ing aer­o­bat­ics and ex­pand the aer­o­batic en­ve­lope. And, yes it should man­age a ver­ti­cal roll and be com­pet­i­tive at In­ter­me­di­ate level con­test aer­o­bat­ics.

One last thing a club or pri­vate owner will want to con­sider is the price, which is $275,000, (cur­rently equiv­a­lent to £207,000). This com­pares well with the Ex­tra 200, which is listed at $370,000. I wouldn’t like to in­struct tail­wheel in the Ex­tra, though, and you could in the Xtreme De­cathlon. Like Pa­trick, you could even have your pri­mary PPL train­ing in one, though a Cessna 152 would be eas­ier.

You could in­struct tail­wheel in the Xtreme De­cathlon... you could even have your pri­mary PPL train­ing in one

180° per sec­ond roll rate is high by tour­ing air­craft stan­dards but mod­est for an aer­o­batic ma­chine

Se­ri­ous up­side-down fly­ing ca­pa­bil­ity, thanks to the en­gine’s in­verted sys­tems and the De­cathlon’s semi-sym­met­ri­cal wing section

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.