Official Dynam 1500mm B-26 Marauder Thread

[ruffneckx1]

I may have missed something along the way but I haven't seen too many finished products from the 3D files.

Woody

[NoDirt!]

I may have missed something along the way but I haven't seen too many finished products from the 3D files.

Woody

Yea, I havent either but think they'd be a nice addition.
Mikey 68 had some made but he sold them.

[Bearcat]

Flew the B-26 again today and once again, retract failure while in the air. First, only one retract came down, then after cycling, none came down. I had to land it in the tall grass. Belly flopped it with no damage. I read in the other forum that Dynam retracts may not work below 60F. I think this may be the key to the whole situation. I was flying near freezing temps. Right out of the warm car, the retracts cycled no problem. About 1/2 way into the flight, I tried the retracts and that's when the problems started. As I got further into the flight and the more it flew through the cold air, none of them worked. This is a real bummer. I like to fly all winter long, so unless I replace these retracts with a suitable non-Dynam gear, this thing is done till next spring.
I think Dynam needs to re-think their choice in retracts and use something from the FMS or Freewing bin. Those things have worked for me to well below freezing temps. No matter how interesting the next Dynam product may be, I will buy it with the notion that the retracts will have to be replaced immediately.

Yeah my A-10 is bad about that once it get below 50 degree so either get use to it or leave the gear down...and I have owned my A-10 for about 5 years now.

[Veltro]

In the last week we've test flown three Dynam B-26s: Bird Dog Special, Klank's Tank, and Rosie O'Brady. All three have the CG set at the third panel line from the leading edge (70mm), and the throws set at 1/2 inch for elevator and 5/8 inch for ailerons, with expo on both. Klank's Tank and Rosie O'Brady have the 1/8 inch horizontal stab shim, while Bird Dog Special has a modified thrust line on both engines. This was done by adding one washer to each of the bottom engine mount attachment points.

We found that you have to include a very small amount of rudder to coordinate the turns or she drags her rear and looks like she is tail heavy when she's not. I'm going to mix in a few degrees of rudder deflection for my next flight.

Here's a clip of Bird Dog Special doing a little "IOE training" the other day:

[rifleman_btx]

So what seemed better the shims or the thrust angle? Interesting ideas :)

[rifleman_btx]

Any word when the next parts shipments will be in?

[themudduck]

Veltro, I agree with the rudder suggestion - I've been using a 35% mix since the beginning and find it very helpful for the same reason.

But 70mm for the CG seems way too far back. There are other specific aerobatic tests you can do to see if the plane is balanced, besides normal flight. I'd like to see your reports on how your planes tests at the 70mm position.

[themudduck]

For example:

Assuming your bird is trimmed so it flies level at a medium-high power setting. Fly into the wind.

1) Drive Bird Dog Special along flat and level and then pull up steeply to a 45-degree climb. Then let go of the sticks.
A tail-heavy plane will continue to pitch up by itself. A nose-heavy plane will pitch down by itself. A neutral-balanced plane will continue the same line.

2) Get some altitude, the fly straight and level, pull up a bit, and then roll inverted. A balanced plane will need a little down-elevator to stay level.
If you need a LOT of down-elevator to stay level, its nose heavy. If you need no down elevator (the plane stays level or actually climbs inverted) then its tail heavy.

3) I don't recommend this test for the B26... but here is something else. Again, assuming your plane is trimmed. Take your plane WAY up and then put it in a steep dive (45-degree down) with the power on. A tail-heavy plane will tend to pitch down further all by itself. A nose-heavy plane will pull out (some). Problem with this test is that you will need to reduce power and pull out at speed, and a tail-heavy B26 is really hard to pull out without snapping. That's why I wouldn't suggest doing this!

At 65-70mm my plane headed up all by itself when I did the first test. So I'm flying at about 57mm. And it still snaps like nobody's business....

Most of us prefer to fly a bit nose-heavy. A true neutral position is really for aerobatic planes, so I'm not saying you should make your plane exactly neutral. I'm only suggesting the tests to find out where the neutral point is....

[Ted7rns]

A Tale of Two B-26 Shims.

We flew two B-26's today one with the Shim on the Horizontal Stabilizer (Klink's Tanks) and the other shim the motors up some, then just trim the elevators (Bird Dog Special). Both flew great and we had some fun today. Thanks for the video Kenny.

Our Squadron is growing, we are up to 4 B-26s.

[Ted7rns]

For example:

Assuming your bird is trimmed so it flies level at a medium-high power setting. Fly into the wind.

1) Drive Bird Dog Special along flat and level and then pull up steeply to a 45-degree climb. Then let go of the sticks.
A tail-heavy plane will continue to pitch up by itself. A nose-heavy plane will pitch down by itself. A neutral-balanced plane will continue the same line.

2) Get some altitude, the fly straight and level, pull up a bit, and then roll inverted. A balanced plane will need a little down-elevator to stay level.
If you need a LOT of down-elevator to stay level, its nose heavy. If you need no down elevator (the plane stays level or actually climbs inverted) then its tail heavy.

3) I don't recommend this test for the B26... but here is something else. Again, assuming your plane is trimmed. Take your plane WAY up and then put it in a steep dive (45-degree down) with the power on. A tail-heavy plane will tend to pitch down further all by itself. A nose-heavy plane will pull out (some). Problem with this test is that you will need to reduce power and pull out at speed, and a tail-heavy B26 is really hard to pull out without snapping. That's why I wouldn't suggest doing this!

At 65-70mm my plane headed up all by itself when I did the first test. So I'm flying at about 57mm. And it still snaps like nobody's business....

Most of us prefer to fly a bit nose-heavy. A true neutral position is really for aerobatic planes, so I'm not saying you should make your plane exactly neutral. I'm only suggesting the tests to find out where the neutral point is....

I don't know if we need to fly it to check if it's nose heavy or not... It seems to fly great with the CG out of the box, we didn't have to add weight (There was no weight in the tail). I don't remember the measurement of the CG, This where Motion RC said it should be.

This where the CG's for us. We pretty much try to fly it scale, like a B-26 should be flown as. ;)

[TiredIronGRB]

Welcome to Hobby Squawk Ted, I think you'll really like it here :)

[Ted7rns]

Welcome to Hobby Squawk Ted, I think you'll really like it here :)

Thanks ;)

[Bearcat]

A Tale of Two B-26 Shims.

We flew two B-26's today one with the Shim on the Horizontal Stabilizer (Klink's Tanks) and the other shim the motors up some, then just trim the elevators (Bird Dog Special). Both flew great and we had some fun today. Thanks for the video Kenny.

Our Squadron is growing, we are up to 4 B-26s.

I noticed that Klink's Tanks has the same issue with the wing as mine.. it's not flush with the wing where the halves screw together.

[Ted7rns]

I noticed that Klink's Tanks has the same issue with the wing as mine.. it's not flush with the wing where the halves screw together.

Yeah I know... Don't know how to fix it... Maybe the wires not tuck away enough.

[Ted7rns]

Here's another video we did as well... Same flight as above, just a different view.

We like this new forum site. We love Motions, we have bough 60-70 warbirds from Motion. Everyone of our Squadron mates buying the same aircraft so we can fly formations together.

[themudduck]

Yeah I know... Don't know how to fix it... Maybe the wires not tuck away enough.

Bearcat, Ted7ms, check the wing mounting pads (inside the fuselage) - many of us have found that they are not glued in very well, and can pull out. This will make it so the wing won't seat properly (and the whole wing can pull out).

That's some nice flying Ted! Great video!

[rifleman_btx]

Love the videos! They look great!

[Bearcat]

Yeah I know... Don't know how to fix it... Maybe the wires not tuck away enough.

I opened a ticket with Motion RC and sent in the pictures I have posted here, they said this is the first time they seen this, but now this is the second case of it we have seen.
I have checked everything and even measured the thickness of the wing and the inner wing thickness and checked for loose parts, everything is tight - and the wires are not outside of the tracks so there is no pinching going on there. If I can get somebody to measure the thickness of the inner wing where it bolts to the wing and then compare it with mine then it can help find the problem.

But Klink's tank flew fine like this correct?

[Bearcat]

Bearcat, Ted7ms, check the wing mounting pads (inside the fuselage) - many of us have found that they are not glued in very well, and can pull out. This will make it so the wing won't seat properly (and the whole wing can pull out).

That's some nice flying Ted! Great video!

It's the outer wing we are talking about and where it bolts on to the main wing..

[themudduck]

It's the outer wing we are talking about and where it bolts on to the main wing..

OK gotcha. I remember that from a previous post. Its a flush fit on the bottom but there's a gap at the top. Of course the wing mounts are on the bottom side. Do you think that its the wingtip that is causing the problem, or the wing center section? Just curious. I remember when I assembled mine, there was no place to put the wires and cramming them into the small pocket was the only way to do it. I commented back at the beginning that they could have left more room in the design...