Tonight I decided to start the tail pieces on the 'Chip. I got the elevators hinged, but the horn isn't in yet. The airfoil is sanded into the vertical stab. The parts fit is so good in this kit, I took a close up shot of the three pieces in the stab and rudder just to show it. There is still shaping to do and I'm going to do that tomorrow night.

Man, it's great to see you building again. Too many years gone by. Great time out there at the field today. I have all three of your beater planes ready to go. F51 got an old H35 OS, the white thing got a Fox 15 and the foamy got a Veco 19 put on, which is probably what it had before. No mufflers. Let 'em scream!

Great! Looks like Chris will get at least 3 flight next week.

Clint,

Word of advice: stiffen those elevators as much as you can. The tabs tend to twist elevators in unusual fashion, Umland's kits being as good as they are probably have elevators made out of very light and soft wood. This combination, will cause strange reactions to control inputs. Most of us are used to the effects of 1/4 sheet elevator twist when deflected. The effects of the twist a linear, sort of speak but when you use a tab like on the chipmunk, you will are get responses you may not like.

I did not tiffen elevators on my Van Loo Chipmnuk and when the winds pickup(15+), control dynamics of the model change drastically, making very hard to steer. It's alsmost like flyin a totally differnt model.

Applly a layer of CF vail or double silkspank the elevators.

I have some carbon vail I could put on. I was going to sand a heathy taper into the elevators, but maybe I'll leave them fairly thick. Thanks for the tip guys.

I saw Don's plane live once at Boeing. Man, that was a pretty plane.

Okay, you guys got me a little scared about this now. The wood in the elevators is very light C-grain and does twist some. Now I'm afraid that I won't get them stiff enough to avoid the in flight problems described here. I'm thinking my best bet is to cover them with carbon veil and epoxy. Or is that overkill? How 'bout carbon veil and dope.
I'm also worried that the twisting will crack up the plane's finish. I don't want to eliminate the tabs because it's part of the original design and this is a VSC ship.

What to do, what to do, what to do?

Hi Clint,

If you are REALLY concerned, cover the elevators with .5 oz fiberglass and Z-poxy.  Just squeegie off all the Z-poxy you can.

I don't know if Jim did anything very radical to his (MAYBE double silkspan??) and it was a great flying plane.  We can, and often do, overthink much of all this.  If all the problems we can think of really existed, then we would have heard about them in the past.  Kinda like *tip stall*.  Like Ted says, at the size of our models, tip stall is not a real problem.  But many people obsess over it for years.

Come to think of it, it just might be a kind of "gamesmanship" that used to exist at contests.  Sorta like asking a golfer on the first tee, just before he sets up to swing, "Do you breath in or out on the back swing?"

Bill <><

Maybe I'll just split the difference between panic and ignorance. I'll just use heavy silkspan and lots of paint . Seriously though, is the twisting a real issue here or just a problem someone had once?

Hi Clint,

I cannot say... I had never heard of a problem before Steven mentioned it.......

Gene Matheny....years go (grey airplane above) had an old T Bird that he made a series of experiments with balanced elevators and found that the basic concept has some real merit to reduce the loads that occur on hard corners. He found that the majority of stunt models available in those early daze' often were designed with stab and elevators that were simply too flimsy' built to lightly to withstand the heavy G loads that many stunters would be subjected to (especially in higher wind conditions and again if the models weight was on the "biggins-side"

That grey "Genie Bird" of Gene's was built EXTREMELY LIGHT IN WEIGHT....and in those days we didn't have exotic graphic-fiberglass and beefy glues to HOLD EVERY THING TOGETHER...and often models of that period had some pretty short life spans n' DIDN'T HAVE VERY MUCH LONGEVITY.
 Many were retired early (crashed) from flutter & stress cracks. Gene found that by utilizing those balance tab elevators...this beautiful light weight model of his not only turned more consitantly but also tighter and grooved even better....using the balance elevator principle?
(In my Free-Flight fright  "MINI HOGAN days...etc. IT WAS PRIORITY ONE that the stab and rudders stay EXACTLY WHERE THEY WERE DESIGNED...and contests were alway won or lost...in just how well  the model stayed together during the engine run faze....and then into the transision into the proper circular glide slope path.

Nothing was worse than a stab that was softer and flexed more on one side of the stab or the other. Naturally, this would made SIZABLE changes in the flight path and could make or break an otherwise beautifully built and aligned model. 

It has always never ceased to amaze me just how little  effort stunt model builders give, when it came to the design and built up time spent on  that ALL IMPORTANT STAB-ELEVATORS.
 Especially when IT IS THE STAB AND ELEVATORS that can also MAKE OR BREAK...even the prettiest and well built stunter?
Bottom line:
Whether or not the tab'd n balance elevators are used or not....STABS AND ELEVATORS MUST REMAIN AS STIFF AND FLEX FREE AS POSSIBLE!
Over the years...I have seen more stunters built with stabs and elevators that were waaay to soft and flexible. One modified Nobler that I can remember that I tacked on  TWIN RUDDERS... That model forever BUZZZED AND FLEXED.  In fact it FLEXED SO MUCH (I swear I could see not two...BUT OFTEN FOUR RUDDERS from the blurrr of the flutter.
NOT GOOD!!!
HEY GARY LETSINGER!  YOU REMEMBER THAT MODEL....JUMP IN HERE AND TELL EM' JUST HOW FUNNY THAT MODEL LOOKED AND FLEW!! Any one  who flew that model...was always alarmed and afraid that the whole back end of that plane would part company one each and every corner. That was one really scarey model.

Here are two extremely successful ICON models...that use balanced elevators with huge success

Ok, don't worry about them twisting too much if you take basic stiffening measures. Taper elevators just as you wanted originally! Just make sure to cover them with CF vail and light silkspan. That's ALL that is needed on elevators this small. If you want extra insurance, do what Bill suggests and apply fiberglass. Although epoxy is fine, I still prefer using nitrate to stick it down and silkspan over that. Either way, you will have good stiff elevators.

AMEN...AND AMEN, STEVE!!! YES! GO BOLDLY FORWARD! SHOULD BE A GREAT MODEL AS IS..especially after looking at your extremely artistical' building skills on those photos.