mpro326

I wanted to get responses from Stuka owners on what they have set CG for their respective panes before I maiden mine. I have a DLE 30 on her and have set it to the 25% rule and it is at 13.5 cm. Please respond if I am not in the ball park with this setting. I also had to add lot of lead to the nose even with the batteries strapped to the engine mounts.

kahloq

135mm will be tail heavy. Mine was set at 127mm and it promptly went nose high and stalled immediately after take off.

irocbsa

My Feedback: (12)

I recall balancing mine around 115mm.

mpro326

Thanks guys, I am going to wait a bit to get more responses and average them to get me close. No hurry to get it in air before I get this correct. Patience is a virtue.

kwik

I will have to disagree with Kahloq in this case. Sorry Kahlog!!![]

(We have "discussed" this before...)

Mine was balanced at 13.5 cm, after finding it nose heavy at 12.5 cm.

It is extremely important to follow the manual on how to set the flaps attack angle correctly.

Otherwise there is an enourmous lift effect from them at takeoff.

I set them in parallell with the underside of the wing. It is also important to have them equally set.

The sightest difference and it wants to roll over at takeoff. Happened to me once.

http://www.youtube.com/watch?v=TcQflHxaMXc

http://www.youtube.com/watch?v=3CUTlnEwC4A

kahloq

Everything on mine was set properly regarding the flaps. It did not roll over until after it stalled. It simply went nose immediately and I don't mean just a little. The nose was at about 70 degree angle the second the wheels left the ground. Had the flap alignment been the issue, it would not have dropped the tail that way. Might have wanted to climb a good amount, but nothing a forward push of the elevator couldn't compensate for.....and the ailerons wouldnt have been super sensitive.

I now have a BH stuka and while not as good looking, I painted it, it flies fine.

kwik

Yes, and mine was perfectly fine too, balanced at 13.5 cm, after finding it nose heavy at 12.5 cm.

kinverflyer

I have been flying mine now for over 4 years, CG set up as per the book. It is imperative you get the alignment of the flaps and ailerons right otherwise you will get ballooning and trim issues.

Originally powered by a Saito 1.80, I have now fitted and MT35, using less and less glow engines.

http://www.youtube.com/watch?v=9xBEewkTQPE

ticketec

My Feedback: (2)

Both of my ESM Ju-87's, one a Dora and the Berta were balanced by the book CoG and had no problems.

Thanks

dave

kahloq

There have been 3 revisions in the manual since ESM released the stuka b version. The first had the cg listed at 155mm. The 2nd at 135mm and a 3rd at 127. Glad many of you had success at 135. Mine did not and had nothing to do with balooning or trim issues. There wasn't even time to do squat when I tried to maiden mine. It was over in less then 3 secs. I've stated what happened, how quickly, and whatever else that clearly illustrated it wasn't an alignment issue with the flaps and ailerons. I'm not going to debate about it, only provided my experience.

Anyway...I wish the OP good luck when he tries his.

mpro326

Thanks to all who have posted their experiences. I made a typo on my original post. I meant to type 112.5 that is 25% of the wing root which is 450mm the manual I have has CG at 115mm The manual also said to set gap for flaps and Ailerons at around 15mm. I made a form from balsa to measure both so they are all at this measurement. I figure I will be at 115 or less and be safe. I will let you know how it works out hope I will have good news and pics.

mpro326

Kinverflyer and Ticketec what were the manual settings for your birds. I know that different versions had different settings. Since you both had success could you both give me the actual numbers. Thanks

kahloq

If your manual says 115mm, then there is now 4 revisions. However, I do not know if there is a difference between the B and D versions. On my B version, esm had the fuel tank location right over the wing which was a considerable distance behind the firewall. Unless running gas or a glow with pump, I don't recommend having the tank that far back. I would imagine ESM has corrected that design flaw by now though.

STUKA BARRY

I have mine alittle forward of the recommended CG to compensate for the siren and battery that is aft of the CG. I'm powering it with a PTE36R engine so the gas tank will be just aft of the carb which protrudes about 1/2 way thru the firewall. I've been flying a Ziroli Stuka for over 17 years now so the flap/aileron positioning is correct. The wire gear really seems Chinese cheap, but being extremely familiar with the flight charactoristics of a Stuka, they should be fine. If they do start to bend, then I'll go with the Robostruts. If anyone is interested, the props I used on the spatz (siren/generator) are Flyzone rc aero scouts model# HCAQ3485. They need to be shaped on the tips, but they are a correct size.

kinverflyer

My CG setting is 128mm F.T.L.E.

kwik

Another thing worth remembering on all warbirds is;

It is very wise to have two rates of elevator throw to select from. Set one at, say , 75% of the largest throw.

When being unsure of the CG at the first flight; Nothing is more irritating than discovering that the elevator
throw was too much, or too little. A flip of a switch, and you might get lucky!

vertical grimmace

My Feedback: (1)

Regardless of what the manuals say, with all of the corrections they have made, The plane wants a particular CG. Certainly best to follow the advice of pilots that have been successful with their Stuka and have them flying. Crashing because of an At CG is a really lame excuse IMO (even if the manual has it wrong), and I feel the problems encountered with these planes seems to have been more related to the ailerons/flaps being mis-aligned.

kahloq

Unless you were present to have seen what happened with the plane, saying its lame when someone believes it was a tail heavy problem is rather useless and rude.
I do agree think that the OP should take into consideration those that have had success. I know mine acted tail heavy, but doesn't preclude other contributing factors....which might include factory misaligned stabilizers(I did not have an incidence meter when I built it 7 years ago)...or something else.

In any event, I doubt anyone would appreciate having their report of something being called lame when the person saying that didn't witness the event.

Black Drape

Hey Kahlog

I have a couple of questions maybe you could help me with. I cannot land my stuka. I know everyone else's land fine. Do you mix some down elevator with the flaps, or do you even use the flaps. watching some of the videos, I see guys landing both ways. I don't remember where I balanced it at, but it is what everyone recommended on the other forum. It seems to fly fine so I guess I am pretty close. Any suggestions?

Thanks
Ron

kahloq

Well....Im assuming your plane is wanting to climb a good amount with flaps engaged hence your asking about mixing in down elevator? Some of the planes I have do require that, but, the current stuka I am flying, I have not used the flaps on landing yet.

You are right that there's a fair number of people and videos that show the ESM stuka doesn't really need flaps to land....I suppose that might depend on the length of runway you have too. If your plane is balooning a little bit, go ahead and try a small mix of the elevator to flap. You probably wont need more then 5-10%.

mpro326

Well, a big thanks to all who chimed in on my CG dilemma. The Maiden flight went this weekend and the CG was set slight nose heavy at 115mm. She took off sooooo sweet and climbed out to altitude with ease. Just added slight rudder on take off. She landed even better. NO flaps needed. I am excited about the next outing with her. Thanks again to all who contributed to a successful and exciting day. Oh yea, she looked awesome in the air. Will try and take pics of next flight. I guess you can tell I am excited.

kahloq

Great to hear!!

irocbsa

My Feedback: (12)

Awesome job buddy. The plane really flies great and will take a hell of a beating as well. She's a tough bird. Mine got dinged up a time or two two trying to figure out the CG situation as well as the aileron/flap alignment. She picked up quite a bit of weight since the initial build due to all the repairs but the darn thing still flies great. Even at 19 pounds she doesn't need any flap to land. Good luck with your plane. Here's to many happy landings!

gizmospal

I agree that there must be at least 4 revisions to the ESM Ju87B Stuka 'written by kindergarteners' manual, as mine too says Cg is to be at 115. Even with some building under my belt, off and on since 1958, I struggle quite a bit in trying to decipher and build this arf. I am currently trying to figure out how to get the linkage and parts together to hook up the rudder and elevator. I don't like the push pull setup for the elevator, and don't like the idea of having a heavy servo sitting all the way back there for the rudder. I would REALLY like some tips or advice on these matters, and PLEASE PLEASE contact me at my email address of [email protected] as I have a terrible time getting back to these forums and finding my way around on this website. I only bought this ESM Stuka because the BH JU87b is out of production, and went together a LOT easier and was a great flyer. But repairs with the PVC printed covering were a nightmare. Any help there would be appreciated also. Contact me at that address and I can exchange pictures of both and other planes. thanx

Black Drape

hey gizmospal
I ended up putting an extra 8oz. of lead in the nose of mine. I balanced mine from what I read in this thread. It's been a long time ago, so I don't remember exactly what it was, but the plane landed like crap. It just flew like it was tail heavy. I did my own calculations from tips I found on the internet about finding the cg of a tapered wing. What I came up with put the cg about an inch farther forward of what I had it. I thought that might be too much so I went about a half inch. The plane landed much better but I think I might still add another ounce. It also flew better, just felt better all around. Good luck with yours. I think it is a good plane, a guy just has to play with it and find the sweet spot for the cg.

Ron