tevans55

http://www.wingspanmodels.com/Produc...onics/ERS.html

This is the bombdrop I am using and I believe Eldher is also using this system. I have attached a photo of the bomb bay during construction.

Eldher

Yes, I use the WingSpan models bomb drop. It works GREAT. I can add more picts if needed.

I am not familiar with JC EVO engines, so no comment there. Given this is a twin, be sure to buy reliable engines.

I also use the Troy Built Models "Twin Sync" module to keep the engines in sync and provide protection if one engine fails.

mikes68charger

My Feedback: (34)

Hey guys I have been reading throw this thread, and Im looking for a new B25

I had a Hanger 9 B25 electric with $350 worth of sound equipment that just did not do it for me, so I gave it to my bud at a kill deal, Traided for a new DLE20 and $100.

So I have a ESM 74in Corsair and I know how they build, I really like this one over the topflite as I hate moncoat.

But I have to ask are the ones comeing out now have all the problems that the first ones had solved? Ie droping wings?

Thanks Mike

tevans55

They fixed the drooping wings. They are still not quite scale, which I believe is negative 3 degrees but it has been fixed from the originals. This is the best shot I have from the front.

Eldher

Agreed, fixed. Note the company replaced the wing tips for those of us who had the original. I still have the original set that droop about 10 degrees. They look quite silly. :-)

For those interested in the history of the wing on the full scale B-25 ... read on.

The original production B-25 had a constant 3 degrees of dihedral from wing root to wing tip. During initial flight testing with the Nordon bomb sight stability problems developed. The bomb sight would correct the aircraft direction with the rudders. As this was done the B-25 would roll significantly from wing tip to wing tip in a "Dutch Roll" with a lateral side to side oscillation developing. Today we'd say the plane had severe yaw-roll coupling. The engineering team fixed the problem by reducing the height of the rudders and setting the dihedral angle of the outboard wing tips to *zero* degrees. The original plane was modified on site and continued testing. Some sources indicate that the first 10 B-25s were built with the constant dihedral, all of which were modified to the gull wing configuration. (Source "B-25 Mitchell, The Ultimate Look")

NOTE: this is not in the book, just my personal observations and basic geometry. The reason the wings appear to droop down ever so slightly is because the *top* of the wing does droop. The zero degree dihedral is set through the chord line of the wing. Proportionatly there is more wing above the chord line than below it. However these proportions become less as you move from the root of the wing to the tip. Hence the top serface of the wing goes down slightly. Attached is a drawing.

If you are a serious fan of the B-25 you will want to book I paraphrased above. This is a fantastic resource. 475 pages of the finest detail, drawing, and pictures. Including pictures of the original straight wing B-25!!

tevans55

Eldher13-

That's great information, thanks. I'm feeling a little droopy now!

Eldher

LOL ... any time!

mikes68charger

My Feedback: (34)

Hey guys I'm glad this bird is back in stock. I'm holding to have the funds on Monday.

Few ququestions I see some have flown this bird with DLE20 but I just saw a clip on YouTube of a guy with a pair of DLE 30s

I really like my birds over powered as we have a short run way.

Anyone done this yet?

also the ESM v3 retracts are out of stock. Did you guys like these retracts

are there any Robart or another brand retracts you recommend?

tevans55

mikes68charger-
I have flown this plane at 33 lbs+ with DLE 20's and it is over powered. On the maiden it took off at about a 45 degree climb until I dialed in some down elevator. My spotter and I were amazed that it had the power to climblike that and not stall. The 20's are PLENTY of engine for this plane and fit really nicely into the alotted space.

Part of the reason my plane is heavy is that I added Robart wheels and brakes. My retracts are from Century Jet and are the prototypes that are a drop in fit for this plane. I also increased the wheel size to a more scale 5.5" diameter. Nose wheel is a Sullivan wheel. Here is a photo of the retracts, wheels and brakes. They are well built and very stout. Hope this helps.

Eldher

I would not use the ESM retracts ... again. I used them on my plane for the first 15 flights or so. But the metal is too soft and slop develops very quickly. I replaced them with Robart gear and brake system. It has been wonderful. The Robart set up is not "drop in" and I bought mine before CJ came out with thier drop-in version. I would likely use the CJ set if I was building the plane today.

I run Saito 150s (24cc) and the plane has lots of power (and my field elevation is 5000', so I loose about 15% of the engine's output). My concern with DLE 30s would be vibration damage over time. The plane was not designed around this kind of power and you might suffer stress fractures over time.

mikes68charger

My Feedback: (34)

WichRobart gear did you use?

Bumsteer

Unfortunately I have a set of used Century Jet retracts for this bird. I had an engine flame out and lost the plane. The retracts were not damaged in the crash. I fly with Eldher13 so I could get him to verify the condition. The mains are 1/2" and the nosewheel is 5/8". If you're interested let me know and we can hook up off line.

Eldher

I have installed the folling Robart gear:
- 635RS 90 Degree Heavy Duty Mains
- Robart Straight RoboStrut 1/2"
- Disc Brakes For 4" - 4 1/2" Brake Ready Aluminum Wheels (pr.) (pt# 140)
- 4 1/2" Brake Ready Aluminum Wheels
- 641RS nose wheel retract, 110 degree
- RoboStrut 440/661 (7/16") for the nose wheel
- I am using the original ESM nose wheel

It requires only a minimal amount of work to get the mains to fit. I'll upload some picts.

Eldher

mikes68charger

My Feedback: (34)

Wow thanks guys for the info I decied to get the retracts from Bumsteer So I got that covered.

Im placeing my order on Friday, Im very excited

the only issue I got left is to figure ot the motor issues.

I got a DLE20 and DLE30 sitting on the shelf looking for a home, Im think more of the DLE30 as I will be able to run a more thicker and scale looking prop and I love exstra power.

What is the longest prop you can run before you have ground contact or plane contact issues?

My Hanger 9 B25 that I gave to my buddy was electric at 22 pounds with sound system could still do non scale loops wich made if fun.

I See that Bumsteer used Evolution 26cc motors wich are as strong as DLE30's as far as I know.

But most I talk to say a DLE 20 will be great.

I like over power, I got a DLE55RA in My 74in 30CC ESM Corsair and Love it. But to be 100% honest its only a tad faster than my other 72in war birds withDLE30's but I wanted to run a scale prop.

Im reading throw this long thread, dose any one eles have any motor input?

Thanks Mike

mikes68charger

My Feedback: (34)

So I have read you guys use TopFlite B25 scale guns


Are there any othere Topflite B25 parts you guys use?

Dose the nose copit parts fit?

tevans55

I am using Wingspan Models 50 calibre and gun belt in the nose of mine and a Dynamic Balsa nose turret. Wingspan's gun is all metal the belt clips are metal and the shells are brass (I think). (Of course the tail turret guns of my Doolittle plane are wood broomsticks!) Here are some gun and turret shots. I also included a shot with a 16" 3 blade prop. You could do a 17" but I think you might have clearance problems above that.

tevans55

Mike-

I just checked my prop...with a 17" prop you will have 1.25" clearance with the fuselage.

mikes68charger

My Feedback: (34)

Wow I mine just showed up yesterday. The box was huge!

So I decied To get 2 ASP 1.80 4c at $230 each + the $150 each to convert them to gas (Nitro makes my skin break out)

With gas power will be down a little but should be about the same as the 1.50 4c.

I got a really good deal on a Spacewalker 2 that I will be useing as a test platform to make sure the motors are running the way they should

So question, Im readding about the wings breaking in the center, I just got a new one from the new shippment, do you think they may be dif?

Is there a way to strenthen the center section up with out cutting the skin off? I would like to fix it before the first flight.

ThanksMike

Eldher

I do not believe that they have done anything to strengthen the center of the wing.
The best approach is to remove the bottom sheeting and strengthen the inside of the wing. I realize that this is not what you want to do, but it will definitely do the job. You can look here to see what I did to my wing: http://www.rcuniverse.com/forum/fb.asp?m=9047984

I can not think of a good approach to strengthen the wing without removing the sheeting. In any case you would have to remove the covering ... so why not just go all the way and remove the sheeting too.

ramboman

Very interesting thread...
I will get mine in a few days and looking for power system...
Electric... probably a pair of Plettenberg 370/40/A3 I have... 1500W or 2.0HP each... should be enough ?
10s a123 packs...
Objective: less than 12kg.

Eldher

2HP per motor sounds really good. Should be plenty of power. 12kg is a reasonable target, but I don't think you'll get less than 12. most of the planes are coming out between 12 and 13. Mine came out at 12.75kg. with a completely stock setup. I've added more to it over time and now weighs 13.5kg.

F82FAN

My Feedback: (10)

Mine used Fuji 24cc and was more than enough.

bedrock

Hi,

Everybody fly with twinsync? Or it not nessesary?

kahloq

Some do...so dont. Ive never been able to get mine to function properly, but I probably didnt get it setup right. There are several that fly their b-25's(of any brand) without it and rely on tuning the motors.
Me? Well....I keep the onboard glow units turned on throughtout the entire throttle range so a motor going dead shouldnt happen(although I currently have 3 cyl radials and those are a problem in and of themselves keeping all cyl's firing)