RE: ESM LA-7 From VQ Warbirds
 

Great news about your maiden flight.
Glad it went all ok. Where abouts did you get your info from regarding your C.O.G at 150mm? By the way - mine is the radial powered unit you saw tip stall. OUCH. The memory is still painful. I would recommend winding in a small amount of reflex on the ailerons. This will make the angle of attack slightly less at the tips and "Hopefully" prevent a repeat of the dreaded tip stall.

When I flew mine recently - the cog was at 155mm. It was a little twitchy on the elevator at this setting. It made the landing a bit bouncy.
I have since moved it to 150mm and are just waiting to fly it again when the weather is better. It should track better with a little more weight on the nose.

Great job on the pilot figure. He looks right at home. I would like to find a suitable pilot for mine as I have the same cockpit kit from Ty.
A sliding canopy would be a must have for such a great setup.

Very tidy setup in the fuse. I moved my tail servos to the aft end to balance the big engine. I see you have twin cables off your rudder servo. Did you run a direct line for the tail wheel?

Look forward to seeing a few pics from the field.

Trev.

RE: ESM LA-7 From VQ Warbirds
 

Could you explain this a little more or provide pics? Since I'm going to be building mine soon this sounds like a good idea.

RE: ESM LA-7 From VQ Warbirds
 

Here is a photo of what I mean. Both ailerons are set so that their trailing edges are slightly above the ideal position. This reflex angle lowers the angle of attack. The aim of the reflex is to keep the wing tip flying when the rest of the wing is in a stalled condition. An example is a 3 point landing on these big birds. If the wing tip stops flying before the rest of the wing - it drops. Stalls. NASTY!!!!

RE: ESM LA-7 From VQ Warbirds
 

Hey Kiwi Bandit,


I've seen others do this with their ailerons but I've never understood it. In every case of deflecting an aileron upwards I've always had the wing drop. I've used reflex in a flying wing but on a standard setup with a tail I've never seen moving a surface up increase lift.

If you put an incidence meter on the wing with the surface deflected it would seem you'd get a false reading as the wing cord is not following the center line of the angle your measuring.

If you look at full scale aircraft with lots of washout the leading edge of the wing at the tip. The tip is visibly lower than at the root. Some are very dramatic. In fact some have very blunt leading edges at the wing tip when compared to the root to assist with preventing tip stall in addition to the washout.

I'm NOT trying to go astray from the thread or start any kind of point of contention. Just hoping to learn and show my thinking as I use to do this but stopped it after I really looked at what I was doing.

What am I missing?


Joe

RE: ESM LA-7 From VQ Warbirds
 

You're not missing anything Joe. Turning up both ailerons does not take the place of washout. I just disrupts the lift.

Cheers

RE: ESM LA-7 From VQ Warbirds
 

Yep, so true. By reflexing the aileron you are essentially lowering drag (very slightly) and lift (considerably) so the effect is a more pronounced tip stall. There are many examples of proof of this. Any glider with crow (butterfly) braking is one. The ailerons are relfexed up to produce drag and kill lift to balance the effect of the flaps. Any glider with a marginal tip stall tendancy becomes noticably worse in this condition. Luckilly they tend to have a very low wing loading. Reflexing the entire wing stightly will reduce drag and speed your plane up, but at the cost of lift - any gilder will show this.

If you want to reduce stall speed at the tip then drooping the aileron slightly will probably be better (I still wouldnt recomend it). However washout and camber change are 2 VERY different aerodynamic effects with almost opposite results. Now I'm not trying to argue with anyone, after all this is just my 2 cents, but I have been test flying model aircraft for guys for the last 15 years and designing my own weird and wonderfull planes for 20+ so have learnt some very hard and expensive lessons, and dont want to see models written off due to avoidable mistakes. We all work hard to afford our models, so they should last as long as possible!

Yes the stall on the LA7 is a bit aggressive, but you do have to push it to get a stall. Spitfires and P40's are the same. Just fly within their flight envelope and dont try any 3 point landings unless you are supremely confidant. You wont see too many fullsize warbirds 3 pointed on their test flights!

RE: ESM LA-7 From VQ Warbirds
 

Hey Brett.
words of wisdom. The only other model i use reflex on are my delter wing styles. (Long ezy and jet)

It was Matt who preferred to have a small amount put in.

wheeling it on to the strip looks nice and keeps the speed up if u need to go around.

Trev .

RE: ESM LA-7 From VQ Warbirds
 

Trev,
yer, Deltas and flying wings are a different set of rules - tailess aircraft and all that...

I will tease Matt relentlessly about that. Ta! Hehe, Gota get the boot in whenever I can. :D

Cheers
Brett

RE: ESM LA-7 From VQ Warbirds
 

Oh!! I always called those spoilers. I know what we're talking about now. I find it much harder to stall a plane using reflex (aka - spoilers) rather than flaps. I get in trouble with flaps cause I slow it down way too much, flaps give me a false sense of security at slow speeds. Spoilers kinda force it down while keeping the speed up. Either way, I never use either tell I've got my CG where I want it, then I start messing around with that stuff. Thanks!

RE: ESM LA-7 From VQ Warbirds
 

n8622,

will that twin XYZ 53cc gasser fit into the ESM bearcat?

i know it's a good match for the LA7.

RE: ESM LA-7 From VQ Warbirds
 

jmohn, Like your weathering on your plane but how do you put or what do you use to put on the rivets? I am referring to your post on pg three.Can you post me some more photos of the wing panel lines top and bottom. My plane will be here next week and want to get started asap on the cockpit and weathering.
Thanks,
Steve Mullis

RE: ESM LA-7 From VQ Warbirds
 

Smullis, I was able to get a similar weather effect by just taking a number 2 pencil and shaving some of the lead from the tip onto the plane and then rubbing it in with my fingers and hand. For the rivets, I just put the tip of the pencil in the rivet outline on the fuselage and rotated it to deposit some lead into the rivet depression. One unexpected and very pleasant effect I noticed when rubbing the lead on any of the Solartex covered surfaces is it tended to lightly outline the ribs under the covering and made for a really convincing weather effect of the ribs. After applying the weather effect, I fuel proofed it by spraying on a layer of dull clearcoat. Check out my pics.

RE: ESM LA-7 From VQ Warbirds
 

Miklos, Looking good and thank you for the info. On your wings though are the rivets flush or raised rivets and how do you copy them and make them uniform.I am not to worried about the fuse but I want to do a good job on the wings also.Panel lines and rivets look great on your plane.
Thanks,
Steve Mullis

RE: ESM LA-7 From VQ Warbirds
 

miklos, I was just wondering about this also.Taking a charcoal Briquet and crushing it up real fine and using it for weathering. Use the kind that has not lighter fluid soaked in the charcoal.Then flat clearcoat as you stated. Did you by any chance use the flat clearcoat from lusterkote or a different kind of paint. Since my plane is on the way looks like I am gonna need a airbrush.Nothing real fancy.
Not changing the subject but has anyone used a Zenoah-45 for power yet? I have one in a Gee-Bee Y and I know it will fly the plane ok.Everyone just jump in here and give me your suggestions for this is my first scale project and I want to do a good job. Your help will surely be appreciated. Now TBM has electric retracts for this plane. So had anyone tried these yet? I also want to put a mechanical retract for the tail gear.I want to save as much weight as possible. Thanks all for a great thread. One this though that has me puzzled is how do the tailwheel doors open and close?
Steve Mullis

RE: ESM LA-7 From VQ Warbirds
 

Smullis, the only rivets you see on the wings are the one line of rivets from the leading edge to the tailing edge with a solid line on either side. These were also drawn on with a pencil and I think look quite good at stand off distances.

RE: ESM LA-7 From VQ Warbirds
 

Hi and Season's greetings.

Regarding the COG this is my second ESMmachine, the first is the Ki-84, based on experience from the Frank and from posts regaring other ESMmachines I decided that I would move mine up. In this thread there are comments about using 160mm, seeing as I prefer slightly nose heavy and by lttle more than luck iwth the battery position, I could move the COGup without adding any weights sooooooo; keeping the mantra that fly nose heavy fly bad, tail heavy fly once in mind I thought I would give 150 a try. When I taxi tested the plane the COG would have been well ahead of 150 and it displayed pretty good ground manners with no noticible desire to nose over I was willing to risk it. With this setup my elevator aligns well with horizontal stab. however inverted flight takes a lot of forward push on the stick (about and heavy third or more) split S's are real easy :-)!!! Also with this set up I have no mixes with the flaps and very little pitch change going from partial to full flap. It goes where its pointed with no desire to move around, slow rolls can be done but with forward stick when inverted. Pitch is easily controllable and not "twitchy".

Yah the way that the cockpit turned out and with the pilot and opening cockpit should be there!! Maybe next time!!

I was thrilled to see that you got yours repaired congrats on that!!

Cheers

RE: ESM LA-7 From VQ Warbirds
 

Hey Guys,

How would you go about doing a sliding canopy for the LA-7? It has a place for a standard rail in the rear but how would you handle the front of the canopy?

My cockpit kit shipped today so I should be able to keep going this weekend. Told you this is going to be a slow build.

Joe

RE: ESM LA-7 From VQ Warbirds
 

Great Speed...maybe I will get lulled into thinking I will catch up to ya on the build:) That may be wishful thinking on my part...are you glassing your wing and stabs? The closer I get to this build the more appealing glass is:)

Merry Christmas:)

RE: ESM LA-7 From VQ Warbirds
 

Hi n8622t,

Funny sometimes things just seem to go very slow. Then all of a sudden the build takes off.


I received my cockpit yesterday. It looks very cool. I was prepping to glue the wings and noticed I had a high spot that made the two half's rock slightly when fitted against each other. I put a straight edge on them and found the spot I think. The outer ply face of one of the wing root ribs didn't get glued secure. So that bit of the rib"bump" out a little. I sanded it it some, and will re-glue it to push it back into place.

I'm hoping to get some real progress done this weekend. I'm sure you'll be up to me in no time. My only real time constraint is I want to be done in time to build my DR-1 and have both ready in late March.

Merry Christmas:D



Joe

RE: ESM LA-7 From VQ Warbirds
 

Hey rare bear, sorry so long to get back to your question...the engines measurements are posted earlier :D Im not sure what the Bear Cat cowl measurements are but it needs to be around 10 inches

RE: ESM LA-7 From VQ Warbirds
 

post #308;)

RE: ESM LA-7 From VQ Warbirds
 

thanks, i saw that awhile back.
i just need to know the cowl size - could not find it on the troy site.

RE: ESM LA-7 From VQ Warbirds
 

Rare Bare, The cowl dims for the LA-7 cowl are 91/4" Wide And from the firewall to front of cowl is 61/2" The opening on the front of the cowl is about 6".
Steve(Redman)Mullis

RE: ESM LA-7 From VQ Warbirds
 

Hey Speed I almost have the P-40 finished...getting close to balancing then do a little weathering...but the best part is that the LA7 is finally coming out of the box:D

RE: ESM LA-7 From VQ Warbirds
 

that's perfect. this may be the plane i end up buying.
i need to see the bearcats cowl first and get the dimensions.
it's between these two planes i wish to build next year.

what is the final weight of the LA7 with the 53ccengine?