vicman

My Feedback: (10)

Last year at the Speed Rally I was given a well used Magnum for future use.
I really love how the Mag sounds in the air at full warp with the cool whistle and Bad Boy looks.
However it is a horrible build with the fat TE on the wing and tail. So with the gimme bird (thanks Skip) I plan to clean it up a bit and see what happens.
Not sure what engine I'll mount in there yet but I have some serious HP available and won't disappoint.[>:]

Pics of mods to follow.

evan-RCU

Vic the fat TE doesn't hurt the speed or flight. Jeff Gilbert said to keep the fat TE on the Diamond Dust as it reduced flutter at high speeds. I do agree it looks better and when I built Mag-2 thinned them, didn't see a difference in flight.

Good luck with the build.

speedracerntrixie

My Feedback: (29)

The thick TE will make the airplane more stable around center and make control surfaces more effective. IMAC guys have been taking advantage of this for years. Aerodynamically we don't start seeing advantages until close to 200 MPH unless its a sailplane. Sharp TE done right does add that certain seriousness to a speed model though.

combatpigg

My Feedback: (3)

The thick trailing edges on delta elevons leaves them with more structure to resist flutter.
[I've never experienced elevon flutter either way]
The blunt, "flat plate" control surface gets into the airstream with less deflection from neutral..so this would contribute to sensitivity..or in other words quicker response from neutral. I think most control line precision aerobatics flyers [who get down graded on every slight burp their models make] would say sharp trailing edges promote smoother tracking and less sensitivity around neutral control.
As far as RC speed planes go....thick trailing edges just look "hen house"...........

Rudeboy

The only thing I've ever had flutter on was the barndoor ailerons on a 100" Telemaster, controlled by ONE servo you wouldn't use for your throttle these days. And that was in a dive.
If the structure is sound, the linkage tight, and the servo up to the job...I really don't see a sharp TE edge going into flutter.

Other than that, I agree with CP: it looks sharper when it's sharp!

speedracerntrixie

My Feedback: (29)

Pattern and IMAC airplanes have been going to thick TE for a while now. I agree that the look is odd but the result is worth it. I would agree that the effectiveness around center is better and thus on a CL model could be twitchy. R/C guys would just dial in a little more expo, CL guys would move the lines in on the handle both would benefit from the higher degree of control close to center. At least that is what the CL sunt pilot I hang out with seems to think. We are gearing up to make him a set of thick TE elevators and flaps now. My race planes do all have razor TE, to keep them strong and still the whole stab and fin are glassed with 2 layers of 1.5 oz cloth and bagged. The elevators and rudder are separated after the bagging process.

john josey

Looking forward to seeing what mods you go for.

vicman

My Feedback: (10)

I'll post a few pics when I have enough progress to show.
Interesting that this mod would generate so many replies from guys who I respect on speed stuff.
Two things drive me on the mod thought. A fellow racer who was the stuff back in the day told me "putting the air back together is just as important as how you took it apart."
My own foolish logic is that none of the 422, F3S, F5B planes that I have seen use thick TE. If it works for those guys, it should work for me. This logic has worked pretty good so far in other areas of fast planes the I have applied it.

One mod I am struggling with is to skin the hinges. I would really like to do it but that would mean glassing the wing and I don't see much benefit coming from the added weight.

I would be happy if this thing broke 175 at the rally. So far low 150s is all I have been able to milk out of one.

combatpigg

My Feedback: (3)

Vic, about 2 or 3 years ago Sessholvlaru got a Magnum to do 195 with a side exhaust Nelson and APC competition props if I remember correctly.
He quit posting at 195 mph and not very many attempts [that got posted here at least].

Rudeboy

Flat out, or out of a dive...?

Q40 motor are awesome powerplants

vicman

My Feedback: (10)

I have kicked around putting a Nelson in there but don't really think it will make a 50mph difference for the risk of a great engine.

RB, At the rally there are no flight pattern rules other than two passes from either direction. A dive is ok if that's what you want to do.

combatpigg

My Feedback: (3)

[link=http://www.rcuniverse.com/forum/m_9256023/mpage_2/key_/tm.htm]Bad Ass Magnum..!!![/link]

Rudeboy.....here is the link to a pretty interesting thread that happened while you were away.
[not as good as a German speed thread, but pretty good for North Americans....]