Official Dynam 1500mm B-26 Marauder Thread

[Mad Baron]

It was at full speed it just wouldn't rotate

[CFIT rob]

TS..its true you do have to go thru the airplane to fix or check multiple things (more than most)but it is less work than it sounds like and most of it is not uncommon eben on flightline birds(needed up ELE on the p38 incedence problem, loose control horns on the avanti, cold solder joint on a motor connector cost me my p38, ) It is a good flying model with great flight characteristics when set up properly (like any aircraft). For a price point,only one of its kind aircraft its worth the work. It looks so cool on a blue sky day, flying across the clouds. I do wish the quality control was better. With MRC involment i expect it will.

[CFIT rob]

Mad baron.. i am having good success with mine,Cg of 60mm, 1/2 flaps on take off, slowly accelerate to wot. I had issues with QC like most(all?). Addressed issues as noted on this thread. My first flight i didnt have 2mm up ELE and almost ran out of up trim. Also had a Cg at 50 ish mm. I did start with ELE travel at 1/2inch travel. I am still flying without the stab mod as it is not a necessity but plan on doing it (i like the idea of "cleaner"aerodynamics.) Are your wheels ok? A hub on my mig 21 melted on my first highspeed taxi test,made it veer off centerline.

[Mad Baron]

I set up my cg at 60mm and used half flaps for take off this would have the maiden flight so there was not any sort of drag on the wheels. I have put so much time and money getting this plane ready to fly before I tried to fly it I rechecked everything before I set it on the runway.

[NoDirt!]

Hate to ask but, aileron travel correct?

[rifleman_btx]

Have you checked the spar/ wire covers on the wing ends?

[rifleman_btx]

And I'm still waiting for the canopy set... :/

[Mad Baron]

All of the control surfaces are correct I do a full check of the control surfaces before the take off roll.

[rifleman_btx]

Reason I asked about those covers, that's exactly what my plane did in the exact same way. And the reason was one of the covers came loose and let the wing tip lift from the spar

[Mad Baron]

I just checked the covers on my plane and they appear to be secure. I am hoping to remaiden it next week I have repaired the damage. I hope the next flight will be successful! Here's a pic of it before the unsuccessful maiden.

[rifleman_btx]

Sounds good, hope this one goes much better

[quitcherbitchen]

Since the Bi Fold doors are way too complicated I decided to redo my fiberglass Bomb Bay Doors. This time I wanted to make a little overlap so the doors wouldn't cave into the bomb bay if I gripped it from underneath or had to make a belly landing. I learned from my earlier attempt to make the doors that 2 layers of 3oz and .07 oz layer was just too flimsy. This time I did three layers of 3 oz.

[borntoolate]

Nice work, Adam!

[themudduck]

I just checked the covers on my plane and they appear to be secure. I am hoping to remaiden it next week I have repaired the damage. I hope the next flight will be successful! Here's a pic of it before the unsuccessful maiden.

Its a real nice-looking model MB, I hope you get it fixed back up. From the pics I just can't tell if you have done the shim for the stabilizer. Without the shim, you do have to have up-trim set on the elevators, at least 3mm up. Its sitting there with level elevators and without any shim, its not going to want to take off like that.

[Mad Baron]

I did install a 3mm shim it doesn't look like it though. I was inspecting the elevator throw today and noticed one side of the elevator had more throw that the other one and I put some CA on the pushrod tube as it was moving with the push rod now both sides of the elevators have the same deflection. I am thinking this might have caused the crash on takeoff. I am glad that it didn't get air born it might have been worse in the air. Its all back together again except for a couple of battle scars when the prop broke it cut a small gash in the wing.

[DavidCalder]

I've been told on one of my facebook groups to shim the horizontal stabs, unless I don't mind lots of elevator trim, what's the required amount of shim? Mine is in the mail on its way.

[borntoolate]

It looks like 3mm is what is needed for the shim.

[themudduck]

MadBaron, Brontoolate, David Calder,
I took some more pics and a short video at the field today.

The pics show my shim - installing the shim corrects the incidence of the stab and makes the model fly a lot better. Without the shim, you need a bunch of up trim and flying like that causes some aerodynamic problems (in effect your stab is undercambered). I used a 2mm shim plus I lowered the LE of the stab by sanding down the front of the saddle by 1mm. Same difference as the recommended 3mm. In the pics the shim is unpainted white Depron foam.
Its important MadBaron to check that the two elevators are set exactly the same deflection, like you said.

By the way I have also mixed a little rudder in with the ailerons, that helps a lot in the turns.

You can also see that I've used the middle hole in the elevator control horn (less slop) and I still have a few mm of up trim set.
I also took a picture of the 3600 4S battery to show the position - its almost all the way forward in its tray. I stuck a piece of foam behind it to stop it from going further back. (I also removed the tail weights)
Last pic shows the new wheels (the nose wheel is slightly bigger than the stock wheel - which raises the nose slightly and helps with takeoffs)
Main wheels are 2 3/4" (DuBro) and the nose wheel is 2 3/8" (Dave Brown).

Link to the video: https://youtu.be/Ds3McW7c-QA
The video just shows a quick demo with a pair of takeoffs and landings, using the flaps, and shows a closeup of the stab showing the small amount of elevator throw I'm using. I've made better landings, but it is what it is!
First landing was faster than usual... second landing features a bounce then a nice flare.
I just wanted to show that the model will take off from grass without any problem.
I flew this model three more times this afternoon (full flights) and made some beautiful landings! Of course no one taped them!!

[Bearcat]

Guys the wing hatch fix I used was simple, I figured that one of the magnets was flipped and the polarity was repelling the other magnet- so the hatch was not sitting correctly. So I removed the mount and flipped over the magnet and reglued it-- worked like a charm!! So the front was not seating well either and it appeared that the lower magnet was set too high in the fuselage so I removed it , small amount of cutting and lowered the magnet mount by 2-3 mm and glued it back in - hatch now fits well.

[Mad Baron]

themudduck

Thanks for the advice on B-26 I am going to sand the front of the saddle on the vertical stab and see if that helps with getting my plane air born. Where do you have your CG set? Mine is at 60mm.