Official Dynam 1500mm B-26 Marauder Thread

[Wag727]

I got my e-flite 15-20 retracts today and installed them. I used the original struts that came with my bird but had to modify them a bit to clear the retract housing. Also had to elongate the mounting holes a little on all of them. I also had to file down the end of the steering arm because it was hitting the front retract base and I don't want to kill the servo. All in all, took me about 3 hours and she's ready again. I will keep everyone posted as to how she flies now. Just got relieved of my job at Sam's Club as part of the management restructure after the closures so I will be able to fly a little more until I get another job.

[RCFS]

You may find this helpful (excerpted from "Airplane & Radio Setup" manual) http://www.rcflightschool.com/CG%20rules-of-thumb.pdf

[Grossman56]

You may find this helpful (excerpted from "Airplane & Radio Setup" manual) http://www.rcflightschool.com/CG%20rules-of-thumb.pdf

Thanks Dave, guys, I asked Dave Scott to post this for you, hope it helps.

Grossman56

[Bearcat]

Well Thanks to Callie Graphics I have better art..

[rifleman_btx]

Now that looks good!

[Bearcat]

I read last night what happened to the real plane and I was not happy to find out it crashed due to the right engine failed on roll out, then landed on a frozen lake but with too much speed and hit shore- telescoped the bird.. no survivors. :-(

[rifleman_btx]

Awe dang :/

[Bearcat]

OK I removed the weight in the back but how much does that change the CG? I was using 55-60 range before- so will this move it backwards to 60-65mm correct?
Anybody take a picture of where they marked off on the wing? what battery are you using?

[ryramZ]

Cg should still be in the same place

[rifleman_btx]

Cg will not change just have to find your battery placement that will be alittle farther aft than with the tail weight.

[xviper]

Taking those tail weights out isn't a good idea. I've got a 4000mah battery as far back as it will go and it just barely balances. With no tail weights, you'd have to gouge out foam to get the battery even further back. All you're doing is changing where the plane balances and it won't be at the prescribed CG. As has been said, CG does not change for any given airplane. With this one, it's a matter of placing the battery in the correct place.

[rifleman_btx]

Wow my 4000 without the weights is just about to the forward end of the mount ramp. Very strange indeed, while my 5000 is pushed back around 2in farther aft the cg is set to 65mm on the button

[xviper]

I suppose what brand of 4000's you have might make a difference. The ones I've been using in my B-26 are Gravity brand that weigh 428g. My Admirals weigh in the high 300's. When I start using those, they'll probably be where yours is.

[themudduck]

I am using a 3600, with no tail weights, and I have a 1-inch chunk of foam behind the battery to keep it from slipping backwards.

I am using the 55-60 point and I find that it flies very well-balanced there (as determined by flight testing for balance).

You can use a bigger battery, and use the tail weights, but you guys are flying a heavier plane at the same balance point. That provides advantages and disadvantages, and consequences.
Heavier planes need more power and penetrate the wind better (higher wing loading). But they crash harder as well.
Personally I've always felt that lighter is better. That's my mantra. Ommmmmmmmmmmmmm

[quitcherbitchen]

Lighter battery as Themmudduck mentioned is the obvious solution. I don't think this plane needs a 4000mah battery. I modded my HSD Zero by taking out all the nose weights adding a Esse sound system and a bigger motor. If flies 10 minutes to 40% on a 3300 4s battery. Super efficient. Normally it would use a 4000 4S as stock. Mine is light and nimble.

[rifleman_btx]

I suppose what brand of 4000's you have might make a difference. The ones I've been using in my B-26 are Gravity brand that weigh 428g. My Admirals weigh in the high 300's. When I start using those, they'll probably be where yours is.

Agreed, I'm just using a standard zippy flightmax. I'm not sure the weight on it, and the 5000s are nanotechs

[Bearcat]

I am using 3600 and 4000 Admirals so I do have them marked inside, I noted that old marks inside and the new ones, the biggest change was the 4000 was moved about 10 mm backwards while the 3600 was moved 5mm forwards and the plane has a slight nose heavy balance and I do mean slight..

[rifleman_btx]

Bingo! There ya go! :)

[quitcherbitchen]

I noticed a few things. One, the horizontal tail has a lot of flex At least mine does. Reinforcing this might be difficult as I would have to make a custom spar. Two, the leading edges of the wing have a lot of mold flash. I sanded this off. Three, the outer wing panels may be able to be warped to put in some washout. Maybe put some shims under the trailing edge and put some weight on it for a few days. All three of these things can maybe tame the tip stall issue.

[rifleman_btx]

I had to add full trim from out of nowhere with mine today, I don't know if I have a warped wing or what but I did max the aileron trim on her today. Other than that she did fly well once she was trimmed. Looped and rolled just fine.