STKNRUD

Need help on CG of the Elan. I started out with the recommend CG but had to use a LOT of down elevator doing rolls and in inverted flight and was carrying about a ¼” of up elevator in normal flight. I moved the CG aft by adding lead in the booms and relocating batteries. It helped a little but now it tends to ‘break’ on modest nose high landings so I think I have gone as far as I can. It still requires lots of down elevator inverted. I know a lot of Elan owners have had this issue. Is there anything else I can do? I am afraid to change the AOI of the stab or thrust angle of the engine as those would just induce other issues. I've also elim nearly all of the elev expo. Love the plane with this exception.

Any suggestions?

Thanks,
George

petera38

Hi George,

I´m not sure that I know the answer(s)....But on the first and second flight on my Elan, the plane behaved "nervously"..i.e. I had to fly it all the time, even when trimmed out!
When recheckingmy CG I found that it was about 5 cm too far forward! According to the manual it should be 25 cm from the T.E. edge. (This is asomewhat conservative CG and can be moved further back)
I moved my reciever LiPos back, so they noware as far back as the back of the tank. (CG 23,5cm)
Haven´t had a chance yet to check out the new CG...but asking my friends, who fly Elan, they claim that the CG must not be forward of the 25cm..rather a little further aft. It doesn´t fly well when too noseheavy....

Another advice was to place a brick under the two aft screws on the stab to raise the stab a bit. I didn´t notice bad habits here...but my next flight will reveal that????

I can´t help thinking, ......that with all the different feedbacks I have read on the Elan....some love it and think it flys beautifully, and others...like you and me think it behaves a bit strange, that Elans and Elans might be different from each others .. due to how they are assembled in the factory...????
Just a thought!

/Pete

gooseF22

Ok
It should sit on the tail booms with UAT full and tank empty. If it doesn't, its too nose heavy. the nose is light in this setup. the CG is about 1/4 to 1/2 inch in front of the front of the gear mount.

What you need to do is shim the rear stab. Put a washer under the rear mounts and try again. Some amount of up elevator is normal for the elan. Also put one washer under the front of the motor. ITS not a big deal to shim the stab and motor. Use one washer.

Instead of adding lead to the tail, move your battery right behind the fuel tank on a plank between the canopy rails. See the elan post I did. Alot of guys did that. It still required up elevator because of the high boom inverted, just a characteristic, but not alot. shim the stab and you will be fine. take out a little trim before.

When you get it right, it will not hunt, and it will not break during a landing on you. You should be able to wheelie down the runway after landing with no problem.

PM me if you need more help, I got over 100 flights on mine, and when its right, you will love it.

JoeEagle

My Feedback: (26)

goose

can you provide a link to the "battery canopy rail" reference? i have read so many Elan posts, i am dizzy.

i like how mine flys, but do notice that i need some down on the inverted flight.

mine does NOT rest on the booms when UAT full and tank empty.

joe

gooseF22

easy to change, can stack two and its right on the CG. I had to keep the weight aft because the I used the super sport motor. No weight was added to the booms this way. It would sit on the booms.

I think you might want to shim the stab first, then if the nose sets down gently, you are probably ok. but it definitely would sit on the booms. I had nothing in the nose. my batts were near the intakes, and the smoke pump was under the main tank. the turbine batt was behind the tank.

I remember balancing it and the balance point was barely in front of the cutouts for the mains. If its breaking in the flare, it might still be nose heavy...

JoeEagle

My Feedback: (26)

No break in the flare for me. acutally, it handles pretty well. but it is balanced a bit further forward. i have a P-120 in it turned down, so i have more weight than you do.

here is my clugy setup.

i really like where you put your ECU. very clever!!

i'll have to remember that for the next plane. still thinking about how cool i want that to look.

joe

gooseF22

You can also put them under the tank. pull the tank tray up and zap it to the tank itself and put a tray underneath for whatever. Your setup is good. forward is ok. If it gets really aft, it will begin to hunt in pitch. I experimented back when, but ended up putting the CG back where I started.

good luck flying it. I really enjoyed it!!

digitech

My Feedback: (10)

do use a 5mm spacer and put it in front of the turbine mount.
it fly,s best with down thrust.
i recomend all my customers , to have the cg indeed that if you take off the canopy it will fall on its booms.

BaldEagel

I ended up with the two A123's under the tank as far back as I could get them and the ECU three cell A123 in between the wheel wells, even got rid of the UAT to bring the C of G back to where I wanted it, and I did not turn down my 120SX the Elan can take the power easy as long as you control your urges in a dive, verticle is fantastic and I used to fly around on half throttle most of the time in fact it used less fuel than my Sprint does with a JetsMunt G90 and same size 2.5L tank.

Mike

Mach1

My Feedback: (5)

George,

As others have mentioned, you need to check the incidence of the horizonal stab.
Set the plane up to where the hatch rails are 0-0 and then check the stab incidence. It should be 1 degree positive. Use washers to correct if necessary.
Also as noted, the engine needs 1 or 2 degrees downthrust, i.e. front of the engine slightly up.

Balance at the 250mm mark per the plans.

tucson

My Feedback: (1)

George'

Are you still flying your XL?.

If you remove the canopy, the surface that the canopy sits on is set at 0 degrees in reference to the engine rails. I found on mine that the rails had a slight positive angle. After you mount your engine if you stand off to the side a little you can look at the top of the engine and see how it sits compared to where the canopy rests against. You can also take a small level and lie it on both surfaces to check the engine incidence.
As everyone is saying you will probably need to put a small amount of negative incidence in the engine to align it properly.

I did on mine and it worked perfectly. Unfortuntely mine does require some down when inverted, but it lands and fly's great where the CG is, so in 100 flights I have left it alone. My A123 batteries sit below the tank as far back as they will fit.

On my landings I can keep the nose wheel off the ground almost to the end.

Hope this helps,

See you at Tucson's Jet rally.

Stan

STKNRUD

Hi Stan,

I like the Elan with the P120 so much I hardly ever fly the XL. I am looking for an airframe for the P160 I have in it.

Thanks to everyone for the CG suggestions.

George

Turbinac

George,
Have a look at the new Boomerang Torus for the P160. The way it flies will knock your socks off and it's good looking too! Am I biased??? Maybe, just a little bit.

tucson

My Feedback: (1)

Alan,

I want one. What will be the delivery date to Dallas?

Take care,

Stan

Turbinac

They are on the ship from China right now. Should clear customs around the end of October with any luck. Contact Patricia ([email protected] ) and she'll add you to the list.