Benifits and dowside of.......

I am wondering about the thoughts of this group on "inline" set ups for stunt. I have flown one, and I know several successful foriegn designs are this way. I am mainly asking about wing C/L-stab C/L, engine may or may not be inline.
???
Thanks,
Bill <><

You are about to start one of those LONG threads with the flames next to it! Bob Baron really explored this setup, but many other ships; too numerous to mention, also had this setup.

As long as the flames are next to the thread and not in the thread. KA-10, and Avanti come to mind for inline setups. Never seen a KA-10, the Avantis I have seen fly recently seem to track and corner quite well. I'm curious as to the pros/con's, because I have been contemplating building both designs at some point in the near future here...

LAST EDITED ON Dec-15-03 AT 12:55 PM (CST)
 
>As long as the flames are next to the thread and not in the
>thread. KA-10, and Avanti come to mind for inline setups.
>Never seen a KA-10, the Avantis I have seen fly recently
>seem to track and corner quite well. I'm curious as to the
>pros/con's, because I have been contemplating building both
>designs at some point in the near future here...
>
>
>Steve

Several of my fathers Classic designs were inline set-ups and the Hawker Hunter was exceptional. I brought this up way back when, that in my opinion, inline flies well except when coupled with trike gear.
He placed in the top 10 at the Nats in Classic with his remake of the Hawker. Others would argue that there is to much dampening on the tail surfaces such as when the flaps are deflected. Dad always felt that all things being equal that dampening was the same inline whether up or down making this a semi-ideal or at least equal. I did not necessarily agree but brought on no challenge because afterall I was only in grade school then. Coincidentally, one of his first stunt designs resembled Barons mid 60's published upright, trike, inline...Dang cant remember the name of it..anywho...it was no great flier but would do the pattern with a Nobler moments and wing.

I think Ted will chime in here and make a case for having the Stab slightly above the C/L of the wing. Also my preference, so as to have some clean air working across the tail surfaces. One thing I noticed, having flown both was that inline doesnt respond well to down trim in the elevators for tracking and turn. While it affects equal turn it also seems to detract from inside turn ability and causes some hunting. Possibly an anomally with the particular plane I flew but I sure put plenty of time trying to trim it and it was possibly in need of more wing area or less overall weight.

Steve,
I saw Tom Dixon's KA-10 fly when it was new, and it looked extremely competent. Charlie Pate just told me that his KA-10 really flew well the other day. A lot of the foreign top fliers do/have use(d) an inline set up. Bob Baron and Bill Werwage are the only two that come to mind as having a highly competitive ship from the USA. Just wondering.
I did have a *little* Junar that was inline, and it did seem to turn equally from the start. Crashed at Rock Hill just before the '96 NATS, and the repairs were not quite right which showed up when I tried to fly it at the NATS. The plane, however, flew great when new.
I like the responses so far!
Bill <><

you might take a little idea from the RC pattern flyers. The vertical location of the wing, thrustline, and stab affect how the plane behaves when it is not flying upright level. The best combination for neutral flying characteristics(easy aileron rolls, minimal control interactions in knife edge) has the wing slightly below the thrustline and the stab slightly above. Inline planes tend to get some control interactions which could affect a CL stunt plane particularly in the wingovers and above 45 deg. On the negative side, the incidence of the stab has to be just right, or you get other not so good side effects like unequal turns.

OK, so I am starting the flame: the inline model is not symmetrical - gyro precession and landing gears somehow does not fit well.

The geoxl I am building is Inline (the wing and stab are) after conversations with Mr. Werwage, he says one of the main reasons he stopped building inline like that was because the p47 is not inline and it is hard to make it semi-scale etc.

His 1994 Junar (it was yellow and won the concourse that year, commonly reffered to as the "little junar" was basically a saturn wing and it was also inline, several people have told me it was one of his better flying planes.)

We will see how it goes, there is of course two schools of thought, some have said that with the stab being in the wake of the wing it will not be as effective, the whole idea in the first place was to make it turn more equally since there was no offset...

I am looking foward to seeing how it works.

>OK, so I am starting the flame: the inline model is not
>symmetrical - gyro precession and landing gears somehow does
>not fit well.
>
>igor

I agree with Igor!

The only thing that I am even the slightest amount worried about is a vertical CG problem, I may end up lowering the leadout guide 1/8th of an inch just in case, other than that, if it is good enough for Mr. Werwage to finish an VERY close second at the 1996 Nats with, I think it will serve me fine.

'm about to start flying a model designed by Mike Starret, the "Eliminator". and it's all inline.

The leadout exit is 1/8" below the centerline.

Since Mike won a lot of contests with it, and considering the words of praise Bob Hunt showered upon it I figure inline can't be that bad.

God bless,

Are we going to end up building planes with leadouts with verticle
adjustments as well as fore and aft?
I ...wonder. ...

Igor, you...

Slick, Slammy, Sibarite, Slippery

Slovak,

I can see the landing gear affecting the simetricity (does this word exist?) of a model, but how does the gyroscopic thing act on the it?

God bless, Ion

PS - Regards from Dr. Rugreb and Prof. Noi Zinum...

Rogi says, rotating disc on nose of your model turning in circle forever left, wants to pitch it up, so drag under the prop thrust line does the opposite and thus is welcome.

>Rogi says, rotating disc on nose of your model turning in
>circle forever left, wants to pitch it up, so drag under the
>prop thrust line does the opposite and thus is welcome.

In that case doesn't the landing gear welcome?

Yes, but not enough, you need also wing drag to be under the prop thrust line. ... at least Rogi says

>at least Rogi says

I'm sorry, but I don't recognize the reference.
Who's Rogi?

I think it's a permutation. Ion started it.

>I think it's a permutation. Ion started it.

That's rigt, Drawoh Shur...

Noi Zinum

You know, Ion is on opposite side of globe, he see my name that way: igoR

LAST EDITED ON Dec-16-03 AT 02:22 PM (CST)
 
Sigh... Why did I wake up this morning?

Perhaps I didn't!

I understand you, you have morning, I have evening and Ion has summer.

Time to go to bed.

>I understand you, you have morning, I have evening and Ion
>has summer.
>
>Time to go to bed.
>
>

Yes, summer's here!

It's not the best season tofly, the wind gets strong, and the olny good hours are from 6 AM to 9 or

5PM to 8 PM (the energy saving timetable makes the day long...

Regards from Zinum and Robgreb,

>>>Regards from Zinum and Robgreb<<<

I know -noI-ther of them

As previously pointed out, the gyroscopic precession of rotating prop turning left around a ccw CL circle should pitch the plane up, and drag of things like landing gear below the c.g. would tend to counter this. Just guessing, but intuition tells me that l.g. drag should usually predominate. Perhaps someone can analyze the relative effects of these.

Past this though, subtle side effects and effects dependent on the particular aircraft architecture must be significant. For instance, a thrust line in line with the wing chord would require longer landing gear or a smaller (3-blade?) prop - but this would affect the precession. It would also lower the c.g. and drag center of the fuselage/engine, as would a piped set-up. Lateral area is also influenced. These might require more fuselage or fin above the thrust line. The raised horizontal stabilizer normally helps by providing a pitch-up drag moment, if precessional forces are more than countered by the lowered fuselage/engine/l.g. drag moment. The success in some planes of a slight positive stab incidence seems to be related. My head's spinning already (so what ELSE is new?).

Anyway, I don't see this as a topic where broad generalizations - covering all models - can be made. Most inverted-engined stunters seem to have a downward pitching moment from thrust, flaps, and l.g., but an upward one from precession and (raised) stabilizer/elevator, fuselage, and vertical stabilizer (and deflected rudder) drag. The amount this balance changes with in-line designs depends a lot on how you arrange the aircraft parts to accomplish this. I like the potential of this topic and wait to hear more.

SK

Bill,
I've been a long time proponent of the non-inline setup for many years, both others designs & my own. Until I flew a good inline model - it was an eye-opener! I have flown a couple of Yatsenko designs that are by far the best I've flown - symmetry of turn & stick forces, tracking the sides of squares & wingover, just "sitting" in level & inverted flight.

However, as Igor pointed out, no model is truly symmetrical due to gyro effects, asymmetric airflow and spiral propwash. Having the stab above the wing only gives "clean air" in straight flight, when the flaps are deflected the increased downwash (upwash?) will have an unsymmetrical effect on the stab. Maybe thats why the high stab responds well to a little positive incidence - in my experience the inline setup does not respond(with anything positive, that is) much at all to messing with stab incidence.
Strictly my thoughts only!
Cheers, Dave

Good so far, but as of 23:15pm EST, there are a few more guys that I know will reply here, so join in!
Bill <><

Ask Alan Resinger about inline setups. I know he and Chris Cox were less than happy with their Berringer GeeBee Sportsters.

I'm building a Skywriter designed by Zhang Xiang Dong / plans by Tom Dixon. It is almost inline, the wing is only 3/8 below the thust/stab line. It worked well enough to win two world championships. I think there is someone from Canada doing quite well with one currently in Advanced or Expert. Plus it looks better than most PA planes IMHO. Andrew Raney

>I'm building a Skywriter designed by Zhang Xiang Dong /
>plans by Tom Dixon. It is almost inline, the wing is only
>3/8 below the thust/stab line. It worked well enough to win
>two world championships. I think there is someone from
>Canada doing quite well with one currently in Advanced or
>Expert. Plus it looks better than most PA planes IMHO.
>Andrew Raney

That would be Kim Doherty and he has built several directly from Zhangs molds etc. He also happens to be a friend of Zhang,'s as he is now living in Canada. Kim loves the plane and has done very well with it. Quite a few of us in the upper midwest area have flown against Kim and it is indeed a fine airplane but like anything else the devil is in the details of trim and set-up.