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On Jun 1, 8:43 pm, "Peter Dohm" wrote:

I, too, have always heard that they were well known for extremely docile
handling; and my very limited experience with models as a kid suggests
that
the docile handling is a common trait of that geometry.



I have a Jodel D-11 and don't consider it particularly
docile, certainly not like a Cub or Champ. It stalls at 40 mph but
long before you get that slow it will start a dangerous sink. Short
wings will do that. 1.3 Vso approaches are too slow. The gear, placed
as per plans, makes the tail really light and easy to nose the
airplane over. My mains are a bit further ahead but it's still light
in the tail and much twitchier in the rollout than many other light
taildraggers.

If you're using Falconar's plans, be aware that the airplane
might come out tail heavy. The original French plans called for
mahogany ply, no fabric on the fuselage or stab, and a tailskid. With
birch ply and fabric and a tailwheel, you'll be out the aft limit
unless you lengthen the engine mount or use a heavier engine. His
F11/12 spring gear is far heavier than the oleos, I think, and I wish
I had the oleos. More work but much more useful load in the end. Empty
weight numbers on the plans are way off.

I don't know why anyone would want flaps on this airplane. It
glides like a brick as it is, and if you want to drop faster just slip
it. It will scare the daylights out of you the first time. No other
airplane I've ever flown slips as aggressively. This one has the all-
flying rudder; the F-series fin and stab might not have such
authority. Flaps and their mechanism would just add more weight and
build time.

Keep that wood dry. If rot gets into the spar, the airplane
would be a writeoff. Building the spar is a major part of the whole
project. Get it straight and get those ribs glued on in perfect
alignment. If they're off, they're off permanently. There's no
adjustment once the glue sets. You need a really long shop, as the 27-
foot spar is all one assembly.

There are no tiedowns provided for. Mine has hand-holes in the
wingtips for maneuvering it on the ground and for tiedowns but they're
too far out and place stress on the tips in a strong wind. Better to
make up some aluminum bands to go around the spar and stick out
through the wing's bottom fabric three or four feet outboard of the
gear attachments.

Dan

Well, I certainly stand enlightened on more than a few items, and that tie
down location does sound like a poor choice.

Personally, I have mixed feelings about the low speed performance that you
described--and feel that I have to ask about the glide ratio at the best
glide speed. Part of my reason for asking is that I personally liked the
Piper Tomahawk, despite its sordid reputation, and it had a good gilde ratio
at its best glide speed--but the version with four stall strips also had a
fast sink. I recall the characteristic, but not the flap postition involved
(possibly due to old timer's disease) and I never got to fly a Tomahawk with
two strips or with no strips--but IIRC, the manual implied that the high
sink might have been replaced with a dramatic stall, at a much lower speed,
on the version with no stall strips. My best recollection is that there was
a 6 knot difference in the stall speed without the strips--but the manual is
inaccessible if I still have it.

OTOH, the balance problems are "interesting" because, although I have yet to
build my own project, I have seen a few interesting issues crop up in kits
as well as plans built aircraft. The most glaring problem that I can recall
was a two seat tandem kit that resembled a high wing ultralight in
appearance, but was always intended to be a very simple registered airplane.
I'll alow the type and manufacturer to remain nameless, but the factory
welded fusalage had been jigged incorrectly when it was welded with the
result that the wind was too far forward and the aircraft was tail heavy--so
that forward pressure was required on the stick as there was no provision
for trim. The good news was that the design CG position was shown in the
plans relative to the wing--and just happened to be the same place as the
wing strut attachment points with provision for balancing points to be
easily attached. That last part really qualifies as an outstanding design
feature--especially in the homebuild arena--and we were easily able to
properly balance the airplane with about 15 pounds of balast added to the
nose. After that, it flew perfectly hands off. (I know that a purist would
criticise the estra weight, and I basically agree, but it made a lot more
sense to the owner/pilot than cutting and rewelding the factory welded
fusalage.) The point of this long winded dissertation is simply that you
never know until you do a full weight and balance, both with and without
people and fuel, and any amateur-built aircraft may very well require
adjustment.

Peter