Any S.Decathlon experts out there?

[hugh flung_dung]

I've recently been asked to do some instructing in a S.Decathlon, but I can't get the thing to flick roll (snap roll, for our US colleagues) nicely. I'm using 80mph with 25/25 set. I've tried leading with both rudder and elevator, tried accelerating the roll early/late with elevator, and using aileron. I'm pretty sure I'm not burying the elevator too much. What's the Decathlon technique?

Also, anything else I need to know about S.Decathlons - vices or nasty surprises lurking in corners?

HFD

[djpil]

My advice is not to flick it at all. Doesn't take much for structural problems to occur. I can find references online for you if you like.
But, to answer your question - rudder and elevator together at 78 kts max. Pretty sloppy at best compared to a Cessna or Pitts.

[tigerbatics]

I agree that it is not worth the effort. The Decathlon is an excellent machine and has given a few people some surprises in standard level competition. But that is what it is- a standard level machine.

In my opinion whilst the aeroplane will perform many intermediate figures it will only do so if worked very hard indeed and in any event not very well. The flick roll is an example. The flicks I have flown have all been very unsatisfactory,except in an avalance where it does go quite well. It fulfills the definition of the flick roll but the whole experience is uninspiring to say the least.

There are no nasty surprises, vices or other snags awaiting in the Decathlon. It is just an honest, easy, but heavy in pitch, basic aero trainer. I think it is a lovely aeroplane. Just stick with standard level aerobatics.

[djpil]

Yes, I should've added that it does a passable avalanche. I enter the loop at 130 kts and add aileron once it starts rolling. Airspeed is low so I don't have the same concerns about the structural.
Mine has a wooden spar but even those with metal spars still suffer failures around the fuel tanks.

[hugh flung_dung]

I'd be interested in pointers to any structural issues; I had a look around the web but failed to find anything.
I last flew one many years ago and thought I remembered getting it to flick OK, but maybe it's a memory failure rather than a technique failure! This one is virtually new (metal spar) so maybe there's been a design or CG change.

HFD

[djpil]

Article on structural problems with a '95 SD online here http://iac35.aerobaticsweb.org/news/...ad-Fall-04.pdf

More in the forums at http://www.bellanca-champion.typeclubs.org/BB3/ (need to register to see that one) and http://groups.yahoo.com/group/CitabriaPilots/

There have been design improvements since the metal wing was introduced so the new ones are better but I would still be wary of snaps (except for an occasional avalanche).

[tigerbatics]

Interesting links djpil! Anyone who tries to fly a Decathlon in the same manner and style he flies a Yak55 probably understands how to fly neither. What a total plonker.

The Decathlon is capable of excellent aerobatic performances and seems to me to be a great aero trainer. Flicks are not a standard level figure and represent one of the most difficult challenges in contest aeros when fractions and possible attitudes and variations are taken into account.

This is a stage too far for the Decathlon. While it can be done it is a profitless enterprise which risks 'enhanced maintenance'. When the stage has been reached where flicks should be taught, in my view after successful completion of several competitions at standard level, it is time to move on to a more advanced trainer like the S2A.

Most American two seat aerobatic aeroplanes have a C of G which is too far forward and this certainly applies to the Decathlon. I suspect that this is the basis of the problem. I have never achieved a proper flat spin in the Decathlon for example. This produces the heavy stick forces and the unsatisfying flick roll. Someone, somewhere probably thinks this a safety feature. I don't. It is just annoying.

[Crankshaft]

Power Settings

Opening up this old thread for a few questions...

I recently got my hands on a Super Decathlon, however the '77 model POH that comes with it is somewhat inadequate with it's 16 pages. (I know there's a later POH out there but I haven't found it yet).

I would like to know what power settings you regular Super D pilots use in:
Climb?
Aerobatics?
Lowest RPM in Cruise?

I have my own ideas as I've been flying it for some time now, but it would be nice to hear some other views.


Cheers

[Dan Winterland]

I fly a standrad every now and again, so I can't answer your power settting questions. Not a bad aeroplane, but not great for aeros either. It's too stable in pitch.

But the one I fly has flick rolls prohibited in it's POH. Something to do with the fuel tanks dislodging after repeated flick manoevres I gather.

[ifitaintboeing]

It's to do with the baffles in the fuel tank. They recommend that you flick roll them with less than half tanks - although, it's been a few years since I've flown one.

Shows 78 knots in the AFM for flick [snap] rolls.
POH: http://samdawsoncfi.com/files/bellancadecathlonpoh.pdf

Some good info here:

8KCAB Bellanca Aircraft Safety Analysis

8KCAB Bellanca Aircraft Rental

ifitaint...

[djpil]

I own a '79 Std Decathlon but I fly a Super D frequently.
Generally use 2500rpm/25" for climb and aerobatics however my '79 POM (similar to that in the link provided by ifitaintboeing), section III, states full open/full increase for climb. Lower RPM helps with noise and typical altitudes for aeros means full throttle anyway. I don't have a POM or AFM for a newer one to hand right now but from memory it wasn't a lot different.
For circuit work I typically use 2300/23" to fit in with other training aircraft speeds.

[Crankshaft]

Thanks for the POH Boeingman... That's what I was looking for. But there are a few things left out even in that one.

25/2500 for climb and aeros is what I use as well. I'll se how 2300 in cruise feels like next time, but I noticed the lowest cruise rpm in the POH is really 2400.

Cheers!

[ifitaintboeing]

Try this from Lycoming:

http://www.lycoming.textron.com/supp...Operations.pdf

and this:

http://www.hb-dbl.ch/91D/downloads_f...ting-table.pdf


ifitaint...

[djpil]

My copy (Oct '74) of the Lycoming Operator's Manual for the AEIO series engines shows data down to 45% power, down to 1800 rpm.
The manual for my 200 hp Pitts has cruise power figures down to 50% power: 2100 rpm and 21.4" and if I have a long cross-country leg I have used that for max range.

[On-MarkBob]

I seem to remember that it flicks better one way than the other, I can't remember which. I also remember that power was required. I goes best going straight up, I can't remember the speed, it was more by 'feel'. from a dive pull up vertical and as it starts slowing down close the throttle, elevater first then full rudder and full power. If you keep the power in, the aircraft will enter a 'slovac' (if that's how it's spelt). From straight up you first go upside down (positive G) and as it spins it winds its way the right way up. Shut the throttle and recover from spin. Great!! and looks impressive from the ground.

[will fly for food 06]

25 2500 is good for climbing and aerobatics when teaching. For the competitions we fly the Decatlon at full power and RPM fully fine. This is at the consent of the owner and of course not for very long when in the box or for a display. If anyone is interested the Decathlon display at shoreham airshow this weekend won the best display award.

[djpil]

will fly for food 06 - good one!