Light twin with good SE performance

[TSevs]

I am working in the Middle East, and I've been asked to research a light twin trainer that has a better SE performance than the PA34. Its hot here and in the summer the PA34 on one engine just wont go up! Anyone got any ideas?

[Chuck Ellsworth]

Some years ago I had a Seguin sp? Geronimo conversion of the Piper Apache. It has a pointed nose, square wing tips , square tail and 180 H.P. 0-360 Lyc.s

It was the best trainer that I have used, the rate of climb on one was 500 F.P.M. and there was no VMC.

The only negative I found was the relatively slow cruise speed of 140 knots.

Look in Trade a Plane as they are sometimes advertised there and the price is quite reasonable.

................ . :) The hardest thing about flying is knowing when to say no. :)

[bluskis]

I was talking to a mechanic who has worked in the hot lands, discussing the PA23 in front of us. This is an old airplane but has a pretty good single engine performance in UK conditions compared to some.

He explained its deficiencies when confronted with 40C.

Perhaps the best people to pose the problem of hot performance to is the limited number of aircraft manufacturers,some of whom may have hot climate versions of their airplanes.

I would be interested to know their response.

[ 23 January 2002: Message edited by: bluskis ]</p>

[Tinstaafl]

You could always use something designed for 6 or 8 POB but limit the load to two.

Or what about the 285HP version of the 55 Series Baron? Again, limit the load to two.

Or use a turbocharged variant of whatever seems best. Or what about an aftermarket bolt-on turbo-normalised version if there isn't a turbocharged model offered. Turbo-normalised may remove some of the maintenance $$$ penalties compared to turbocharged eg reduced TBO etc

Depends on how much you're prepared to spend...

[ 24 January 2002: Message edited by: Tinstaafl ]</p>

[DesiPilot]

Try Seneca II. Its turbo charged 200 hp each engine. It should give you good performance. You can also try Piper Aztech PA23-250. It has pretty good performance, a big petrol gussler though.. .Anything bigger than that gets too expensive for flight training. . .If you can afford it, you can also try either Navajo or Cheyenne

<img src="smile.gif" border="0"> Jatin

[john_tullamarine]

Cat Driver,

I am intrigued .. how is there no Vmca with your modified Apache ?

. .Under US design rules, some small twins have no OEI climb requirement due to the AUW and Vso cutoffs. One just has to accept that the normal sort of twin sensibly appropriate to twin training is a dog OEI .. one can't have one's cake and eat it as well in this regard. Tinstaafl has the idea ... either reduce the gross weight appropriately (the easiest option - minimum occupants and adequate fuel) or up the power (thrust) output by an engine upgrade mod (ie bigger motor) or aftermarket bolt on blowers.

. .Another concern is that one doesn't want to play with simulated failures on other than a small engine for the usual maintenance reasons.

[Chuck Ellsworth]

Hi John:

Yeh, the sucker was controllable in yaw right up to the stall. When Seiguin did th mods to the Apache they put a very large fin and powerful rudder plus a long dorsal fin and you could keep it from departing straight flight with full power with the critical engine feathered right up to the stall buffet. ( or simulated feather ) Mind you I never did actually do a full stall with one at full power as soon as it buffeted I recovered. Anyhow that is what I meant by no VMC. So I guess to be strictly correct VMC and stall were about the same. Also by the time you got the thing into that configuration it was very apparent it was in a very unusual attitude and the low speed was quite evident without looking at that airspeed thingy.

Have you seen one in your country?

Great trainer, great performer.... For a little bug smasher.

[Checkboard]

TSevs, have you ever thought that you may be providing better training, by demonstrating how marginal one engine inop climb is, on a piston twin?

Isn't "Hey look at this - you have to have everything in your favour to consider continuing after an engine failure!"

better than: "Wow! 500fpm on one engine, just like an airliner! No need to worry about EFATO hey?" <img src="wink.gif" border="0">

[john_tullamarine]

Cat Driver,

I am not familiar with the particular mod.

However, you are, indeed, a very brave chap ... in general ..

stall + significant asymmetric thrust = spin

and in the average twin, a spin could well prove to be an interesting experiment, especially if the cg is a little bit aft-ish.

One of the more significant hazards in routine twin training is playing with static Vmca demonstrations at altitude.

[Chuck Ellsworth]

Hi again John:

Hmmm lets see if I can reassure you that I am not a "brave pilot". The experimentation that I did with the Geroinmo was carried out in a very thoughtful and gradual manner. I had never seen a small twin that had such excellent yaw effectivness ( authority for the recent among us. ) All my very careful exploration of the Geronimo flight envelope was conducted solo, I have been involved in the teaching of advanced flight training since 1959, at that time I qualified for teaching a course that was called high command control. This was later included in our aerial application school, it is a very in depth course on how to fly to, and on the limit of the aircraft flight envelope ...safely..

You will note I never did actually stall the airplane in that power configuration. However you can rest assured that the exploration of the envelope was conducted in smooth air and safe altitude and most imoprtant I was fully confident there was sufficient yaw control to ensure I did not depart controlled flight at any point in my exploration of the Geronimo flight envelope.

I guess I had be more careful of how I type my comments as I do tend to get myself in a bind.

I should be down in your part of the world early next year hopefully we will meet.

............... . :) The hardest thing about flying is knowing when to say no. :)

[LAN]

TSevs,

I'd reccomend using the PN68 - fabulous aircraft and a treat on 1 engine. And much better handling charachteristics than the PA34.

Brgds,. .Ivan.

[ 25 January 2002: Message edited by: Ivan the Horrible ]</p>

[bluskis]

Good point Checkboard, I still remember my first post twin rating flight, in a Twin Comanchee,having trained on a PA23.

The practically non existant rate of climb on one engine is startlingly clear in my mind over 20 years later, as is the picture of the tree tops we were skimming over.

I should add that the assymetric condition was part of the type familiarisation, not for real.

The experience has made me think carefully about the desirability of flying marginal twins.

However the problem posed was single engine climb in extreme temperatures, so the turbo suggestions probably make sense.

[Chuck Ellsworth]

Checkboard:

Flying should be based on safety. If the airplane you are flying is capable of 500 FPM climb on one engine you can simulate any lower climb rate by reducing power. You canno't however increase climb rate once you are at full power in any aircraft.

It's like the gun issue:

Far better to have a gun you don't need than need a gun you don't have.

............ . :) The hardest thing about flying is knowing when to say no. :)

[TSevs]

Thanks for all the gen, the current PA34 we have are supercharged, but still gutless in the summer, purchase costs are not particularily a problem and they would like reasonable running costs, hence the 6-8 seater option may not be feasible. The "its better training argument" is great if someone else is doing the flying, personally I'd like the option of going up on one in case I don't have 2. The PN68 Ivan suggested, I'd like to hear more about as I'm not familiar with it.. .Thanks to everyone for the responses so far

[A and C]

The product support for the PN68 is not the best and if you need the aircraft for business this may give you a problem.

It would seem that raw power is what you need and i suspect that this will also be in short supply on the PN68 ,I would sugest that the 56TC barron would be the end to the performance problems.

It is fitted with the lycoming TSIO-540 power plant that was also destind for the duke and because the this was pressurised it had BIG turbos fitted , too big in fact for the barron so it spills most of the air over the side ! but this still leaves you with stunning performance.

Beech and lycoming product support is as good as you are as you will find in the industry but lycoming will not overhaul the engines fitted to the 56TC however they will exchange them for a later model when the time comes for the overhaul so have this in mind if you intend to buy one of these fine aircraft.

[ 25 January 2002: Message edited by: A and C ]</p>

[kala87]

How about the Beech 76 Duchess? Compared to the PA34, IMHO engine-out climbs in the BE76 were easier to handle with less rudder pressure required, and I had no problem maintaining a safe margin above Vmca. The BE76 was nicer to handle in the flare as well, with no heavy pull on the control column required (unlike the PA34). However, this was in the UK at well below gross weights and the Duchess only has 180 HP motors, so performance in Middle East conditions would be less sparkling. Haven't got an airplane manual to hand so can't give you the numbers. Worth considering though.

[A and C]

The beech 76 is not the aircraft for this job if as stated a turbocharged PA34 that will give full power up to about 12000ft is not up to scratch how can an unsupercharged aircraft have a hope of meeting the performance required ?

[Zeke]

Get a turboprop, you are operating at high density altitudes with that heat. Something with aircon would also aid teaching as it will reduce pilot fatigue. A used C90 or similar would be my choice..

Some single engine performance figures for you (note these are ISA SEA LEVEL DENSITY ALTITUDE)

<ul type="square"> PA-23-160 G,-H Apache 180 PA-44-180T Turbo Seminole 180 80 Queen Air 180 PA-34 C/R Seneca (1973-'74) 190 GA-7 Cougar (twin) '77 svc. cells=18,300&4,900 200 335 II nonpressurized/turbocharged 200 58 TC Baron (non-press./turbochg.) '78 Lgt=9/2 204 58 P Baron-Press.('77 ht.-9/6) (range ,190 fuel) 204 E 95 Travel Air (fuel inj.) 205 B 95A, D 95A Travel Air (fuel inj.) 205 95, B95 Travel Air (95 = 4,000 lb. gross) 205 58 P Baron turbochg.-specs thru 1976 205 B 80 Queen Air 1973 thru 1978 210 65 Queen Air 210 PA-44-180 Seminole 212 PA-23-235 Apache 220 T303 Crusader 220 58 P Baron(325) pressurized (range on 190 fuel) 223 D 18 S Twin Beech 225 PA-39 C/R Turbo Twin Comanche 225 PA-30 C Turbo Twin Comanche 225 PA-34-200T C/R Turbo Seneca II 225 PA-23 F Turbo Aztec (prior'77=7 gal more fuel) 225 402B, Business Liner 225 402-A turbocharged 225 PA-31-350 Chieftain ('81=otional fuel) 230 70 Queen Air 230 PA-34-200 C/R Seneca (1972) 230 404 Titan Ambassador II 230 76 Duchess 235 PA-23 F Aztec (prior '77=7 gal more fuel) 235 PA-23-150 Apache 240 PA-34-220T Seneca III;IV(roc=takeoff power) 240 PA-601P pressurized Aerostar ('77 s. cell=26,350) 240 PA-601B turbochg Aerostar (prior'80=less perf) 240 PA-23 D,E Aztec (prior '72 length=30/2) 240 PA-23 C,D Turbo Aztec (C=4 gal more fuel) 240 PA-23 C Aztec 240 414 pressurized-turbocharged 240 PA31 P Press Navajo (prior'77=6 gal more fuel) 240 PA-31-310 Turbo Navajo B,C(prior '80 less fuel) 245 A 65 Queen Air 245 PA-31-310 Turbo Navajo 245 340 pressurized/turbocharged 250 PA-31P-350 Mojave 255 PA-31-325Navajo C/R ('81=optional fuel) 255 401-A &B turbocharged 255 H 18 Super Twin Beech 260 PA-39 C/R Twin Comanche 260 PA-30 C Twin Comanche 260 PA-30 B Turbo Twin Comanche 260 PA-30, B Twin Comanche 260 88 queen Air pressurized 265 B 80 Queen Air - specs thru 1972 265 PA-23 E Turbo Aztec (1971 length=30/2) 265 PA-31-300 Navajo 270 58 TC Baron (325) turbochg-non-pressurized 270 A 80 Queen Air 275 E 18 Super Twin Beech 290 H,J 50 Twin Bonanza supercharged 290 D50,A,B,C,E, Twin Bonanza 290 414A II Chancellor (press-turbochg)('78 span=44/30 290 G 18 Super Twin Beech 300 C 50 Twin Bonanza 300 B 50 Twin Bonanza 300 421 - A & B 300 421 pressurized/turbocharged 300 402C Business Liner II 301 PA-602P Aerostar 302 421B Golden Eagle 305 B 60 Duke pressurized (prior '78t/0 run=2006) 307 A 60 Duke pressurized 307 340 A, II pressurized/turbocharged 315 60 Duke Pressurized 319 50 Twin Bonanza 320 B 55 (SN 955 & up=5000 lb. gross; SN 502 thru 954 eligible 5100 320 PA-60-700P Aerostar (preliminary) 320 411, A, turbocharged 320 E,F,G 50 Twin Bonanza supercharged 325 310 Q 327 310 P 330 310K,L,N (fuel inj.) 330 T-337 H-II Turbo (prior'79 t/o perf=1,620 & 1,000) 335 C55, D55 Baron 335 55 Baron 350 A 55 Baron 350 421C Golden Eagle III ('79 stall=85 mph) 350 425 Conquest I 357 310 I, J (fuel inj.) 360 PA-600,600A,-Aerostar 360 PA-23, B Aztec (B=30/2 length) 365 310 R, II 370 PA-601, 601A, turbochg Aerostar 370 T 337 G-P II, H-P, Skymaster pressurized 375 310 F,-G (fuel inj.) 375 310 H (fuel inj.) 380 310,-A 380 E 55 Baron ('70-'72 fuel=142 optional) 388 58 Baron ('76 & prior fuel=166 optional) 390 T 310 R, II turbocharged 390 58 Baron (300 hp) 394 B 55 Baron (1978 & up) 397 320 Skyknight turbocharged 400 T 310 Q turbocharged 408 A56TC Turbo Baron 410 56 TC Turbo Baron ('67 & '68 fuel=178 optional) 410 PA-31T-500-I Cheyenne I (prior '80 less perform.) 413 425 Corsair 434 PA-31T IA Cheyenne IA 440 T 310 P turbocharged 440 320 A-B-C Skyknight turbocharged 450 B100 King Air (prior '79 serv. ceiling=29,100) 452 A100 King Air 452 PA-31T-620 XL Cheyenne II XL (1982-'83 specs) 470 E 90 King Air 470 320D-E-F, Skyknight turbocharged (D gross=5,200) 475 A 90 King Air 490 90 King Air 525 PA-42-720 Cheyenne III(prior'82 8 gal less fuel) 531 C 90,C90-1 (-1 has increased speed) 539 B 90 King Air 555 F90 King Air 600 100 King Air 608 PA-42-720 Cheyenne III A 625 C90A King Air(LJ-1063 up)(10,100 GW=SN1138 up) 626 F90-1 King Air 632 PA-31T-620 Cheyenne II 660 441 Conquest 715 B200 Super King Air 740 200 Super King Air (prior '79 serv. ceil=31,00) 740 Citation I 500 800 Citation 500 (SN 303 & up = 11,850 lb gross) 800 650 Citation VI 805 650 Citation III (SN 100 and up) 805 Citation I 500/501 (unit-0470 thru -0677 & on) 826 Starship 2000 (2000A=increased spds & weights) 850 S550 Citation SII 860 300 Super King Air (300LW has decr. weights) 867 650 Citation III (thru SN 099) 902 Citation 500 (SN 1-70) 906 Citation II 550 (thru SN 626) 906 350 Super King Air 912 Citation II 550 (SN 627 & up) 930 650 Citation VII 990 PA-42-1000 Cheyenne 400LS 997 Citationjet 525 1,070 Beechjet 400 (400A has increased weights) 1,110 Citation II 551 1,170. .[/list]

[john_tullamarine]

Cat Driver,

I have no doubt that you tread warily.

However, to play with significant asymmetric thrust near the stall is a significant hazard, regardless of care. To do this at altitude offers some additional problems with respect to the numbers.

I wonder if we could entice one of the experienced experimental TPs to comment on the matter ?

It would be a pleasure to catch up with you at some time .... I surmise from your profile that you would represent a most entertaining wealth of yarns over coffee (polite word for a beer or twenty) ... and I can promise several other interesting attendees to make an enjoyable evening out of it .... I was always sure that the Cat reference couldn't be to earthmoving ... now I know ...

[Chuck Ellsworth]

Yes John:

Having received some in depth learning over the years I am very, very aware of the effects of altitude with respect to aircraft handling, and I live at sea level which gives me a slight advantage.

Also I spent two years flying with one of Airbus Industrys top test pilots and received a rather in depth insite into the flight testing of aircraft.

Melbourne will be one of our maintenance stops so we will be there for four days at least. would love to B.S. with you.

I really am not anonymous here so if you want take a quick look at my web site, if nothing else there are some great pictures of some PBy's I have flown in various places.. . . .<a href="http://www.pbyflighttraining.com" target="_blank">www.pbyflighttraining.com</a>

Last but not least I must admit I made a mistake saying the Geronimo has no VMC that just slipped out, kinda dumb of me.

...............

:) The hardest thing about flying is knowing when to say no. :)

[TSevs]

Zeke. .Thanks for the info, we are looking at an aircraft with Aircon, and we are considering a turboprop, its just the running costs that are against the torbo prop, and I'm not sure what the smallest turbprops are, were looking at an instrument /commercial trainer. It souns that the Beech Baron 56TC as suggested by A and C may be worth looking into.. .Thanks everyone

[refplus20]

A light twin is just that ... light on power twin engine aircraft. If you need two engines to produce adequate performance, then when one quits, there is not much going in your favour. You will have less than half of your normal horsepower available to you. Add to that passengers, fuel and 40C temperatures .... not a very encouraging scenario. Remember the Piper Navajo off Long Island Sound that could not maintain level flight on one donk and had to ditch near JFK? I have flown C of A airtests where the aircraft would barely meet the single . .engine climb criteria. The advice I gave to students after they passed their multi rating was that in the event of an engine failure after take-off, close the throttle on the other engine and make an EFATO. Chances are you'll walk away from it.

:) :) :)

[Tinstaafl]

Q. Why do light twins have two engines?

A. Because they need both of them.

[Chuck Ellsworth]

Well, Tinstaafl:

Some years ago I flew a Turbo Commander 690B for a local company, now there was one light twin that sure did perform, even on one engine.

But you are right, to really perform the damn thing did need both of them. <img src="wink.gif" border="0"> <img src="wink.gif" border="0"> <img src="wink.gif" border="0">

.................. . :) The hardest thing about flying is knowing when to say no. :)