RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi Normand.

Could you post some pictures how you installed the air tank and valve for the breakes.

I appreciate it.

Best regards

Marlon

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Marlon,

I used the small airtank in the hole located for the original airtank in the B-25. the one in front from the cokpit. I used a medium size airtank for the retracts and located it in the bulkhead like suggested by TOP FLITE in the Tech note. The proportional airvalve for the brakes is located in front of the air tank (small air tank) next to my receiver. I will take pictures tonight. Brakes are awsome and saved my front canopy many times!!! Our runway is 450 feet and when you land late you end up in the high grass and in a ditch. Brakes always saved it so far.

normand

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Here is a picture of how I installed the Large Air Tank:

Ethan

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Sorry, the picture didn't get loaded. This time I got confirmation.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Normand: Thanks a lot for your information I will wait for the pictures.

Best regards

Marlon

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi Ethan:

Thanks for the picture. This is for the brakes or retracts?

Regards

Marlon

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

This is for the Retracts, my B25 weighs about 21 lbs and the tires are soft, so I don't usually need brakes.

Ethan

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

I believe the O.S. .46 AX has 1/4-28 crankshaft threads. Great Planes makes aluminum and brass spinner hubs that may work.

[link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK241&P=7[/link]

If the threaded portion of the crankshaft is too long, you may have to cut it, or use extra washers. The Higley brass hubs are nice toothey are heavy, brass, but that shouldn't matter, but you'll need a rod of some sort to tighten it.

Tim

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Higley also makes a heavy brass spinner hub AND a brass safety nut to go behind it. Used together they make a nice looking combo and both are tightened with a wrench.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

As an alternative to safety nuts, I've always wrapped my crankshaft thread with plumbers tape (that stretchy white stuff) then screwed the spinner nut straight on. NEVER had one come off, or even loosen.

Cam

p.s. Still working on mine as time permits - just finished adding all the extra aluminium panels, rivets etc and rubbing the whole lot back with 400 grit. Next is to prep surface, then paint all the panels, weathering etc.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

hey tim she flew with full power for the first time today! 6s2p 10,000mah flew 20 minutes at 75% power and still had plenty of power. there are 2 4s 5000mah and 2 2s 5000 in parallel. if one set of batts dies i still can power the entire plane. nice aircraft tim! Should put one out as a kit! 23 # AND STILL FLYS GREAT

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hey Tim,

great to hear from you!!!

I guess you FINALLY got some good weather up there! And how's 'bout some pics?!?

Well, keep 'er flyin'.

Tim

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi
Thanks guys for spiner hubs.
Perhaps, it could be said in the documentation that the spinner included can be used on x, y , engines, but z. In order to order them with all the other stuffs needed.
It would avoid me to pay shipping costs.

See you
ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

tim i was working on my wingspan b-17 and put this off. ill get pics for you. those axi 4130-16 are nice motors! she fly lile a big trainer

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

I put 20 perfect photo into my blog
http://forum.rcdesign.ru/index.php?a...showentry=4913

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Nprmand: Did you take the´pictures of your brakes installation? Could you give some hrlp how to set the brakes using the JR 9303. Do you use a mix with down elevator to activethe breaks? I really ap´preciate it.

Regards

Marlon

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

JUST SO YOU GENTS know.... WE are so impressed with the quality of the WINGSPAN MODELS Bomb Release Mechanism and bombs
we will be adding these accessories PERMANENTLY to our ONLINE STORE!

www.vqwarbirds.com
[email protected]

Thanks again MIKE!!!

-TOMAS
VQ WARBIRDS

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Here is a few pics of my Bomb bay with a 8 bomb payload. I can release 4 at a time or all 8 at a time. Bay and bomb rack made out of scraps and 2 servos. Bombs made out of plastic dowl rods. Ron

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hey Brent (Slamdance64). You get the urge to start building your B25 after being at the Giant Rally? Another week and mine should be ready to maiden. Should be ready for next Saturday's event.
Cal.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hey Cal, (Heat1960), yes, more than ever. I can't wait to see all of our B-25's at the field. Of course I will be in stealth mode while ripping along behind you guys at low level!!!
I can't wait to see how yours turned out. Drop me a line when you are going flying and I can check it out (another set of eyes).
Brent

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi guys,

Mine should be ready to maiden next week. Just a question about balance point.
Without lead, the BP is 137mm from the LE.

In your opinion, do I need to install lead in the nose ?
How the BP is set on yours ?

Thanks
ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi ML, With the recommended Hydrimax 4200 4 cell battery installed under the front nose area as per the instructions mine balanced out perfect without having to add any additional weight at all.

Cal.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Balance it gears up and you will get perfect full flaps landing. Also the plane behave tail heavy until you first trim it to perfection. You are better off noze heavy at any time. Mine is bal;anced gears up and flys great.

Normand

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi guys
I use 2 packs : one 3600 NimH and one 2000 Nimh as backup.

Balance gears up : with gears up, the CG shoud go backward. That's mean your's is balanced forward isn't it.
see you
ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Have just started to get this bird in the air and have experienced a problem with the Robart retracts. I fly off a grass runway and find that the front strut bends back. This happened both times I've had the plane up. Seems the pin that secures the strut is made of a soft metal and bends with any form of force on it. Easy enough to fix but what a pain. Any one else experiencing this same problem??? I intend to contact Robart for a solution. Dave...

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi
This is a known problem on this thread. But it happenned only when landing on rougth grass as far as I know.
The issue is this retract is made for lighters aircrafts.

ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hello there Europact74,

I think I was the first one reporting this problem on this thread back in november 2007 and I fly off a grass runway. The event page 23 post 574 and the fix page 55 post 1355. There has also been 2 or 3 other reports of this. I have a fix and solved this problem. At least so far. My B-25 has over 70 flights now and I even had to replace the front wheel due to wear!!! ( plastic hub...). I have posted a picture earlier in january or february and all I did was insert a rubber bushing on the oleo where it squeeze to absorb the shock when it is a bit rough. I have also inserted a picture of the simple fix...military secret!!

The 3/8 strut is designed for 12 pound max planes and the B-25 is well over 20 lbs. when the weight shifts to the front on landing or take off roll the strut is simply unable to resist the abuse and this is mainly due to the shock. I found that the rubber bushing was a very simple solution and absorbs most of that shock.

Normand

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Mdelaruelle,

Yes the CG is slightly forward as per the book but does not behave that way at all. it is in perfect balance in the air. Be prepared for down pitch trim when airborne because when you place it "visually neutral" it will behave as if it is tail heavy and climb. Once trimmed it is so easy to fly and predictable with no bad habits it may become boring. I now take out my B-25 for special events only. It always draw attention and an absolute silence from fellow members watching. I wish they would behave the same way when I fly my corsair, spitfire, P-51...all those flying missiles with all their "gremelins" and bad habits that requires so much attention and skills. It seems that the easy to fly B-25 is the only plane that makes me stand out but this is the secret of whoever fly this Top Flite B-25, it makes us "aces" at the field...if only they knew! Ha Ha!

Normand

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

I wanted to relate an interesting experience I've had with this wonderful aircraft. Ever since I maidened it back in April, I've been perplexed by the seeming instability I've had to deal with when landing. The plane just would not "lock in" on final and always seemed to dance around and yaw from side to side, especially just as I neared the threshold and started my flair. As a result, I always came in hot and usually had more than one go-round'. Well, after I bellied her in due to an air system malfunction( the retaining nut on the Robart air valve came loose and the servo just pushed the valve out of its mount), when I was making repairs to the belly(resheeted with 16th inch ply from the midline out two inches from front gear bay to about 6" aft of the bombay), I had the transmitter on and was making some adjustments to the bay doors. I noticed the left rudder seemed slightly out of position. With the transmitter sitting on the table, the rudder just centered by itself! Hmmm. I picked up the transmitter, put my thumb on the left stick...the rudder moved about an inch! I found that the servo moved the rudder over an inch to either side with me only moving the stick to advance or retard the throttle. There was no problem when the rudder stick was moved to full deflection...everything seemed to work fine. After some detective work I determined that I had a bad HS81 MG. RC Hobbies of Denver happily replaced the servo. The first flight after the replacement was uneventful with the exception of the landing. I made my landing break and dropped gear, reduced throttle, flaps to 1/2. Turned to final, flaps to full pulling the throttle back a little and allowing her to descend. Once I lined up on the runway I waited for the "landing dance" which this time didn't happen! She came down the pipe rock solid, locked in and executed the most lovely nose high landing. WOW, what a difference! I taxied back thinking about what Krproton said about nice SLOW landing speeds. Now I see what he meant! This plane is great, now even better since everything is functioning properly.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

WHEW fytrjok!!!!

I'm really glad your got your plane sorted and can now truly enjoy all the positive characteristics of this model!!!

By the way, for anybody who may live in the midwest, the company asked if I would bring my B-25 to the D.O.G.S event in Dayton, OH on August 29, 30 & 31. I would be honored to meet some of you if any of you are considering attending. I would also be honored to get a group photo of all us B-25 pilots (now I have to keep the thing together until then!!!). I'm not trying to pose as any kind of celebrity - I'm just a guy behind the scenes. There will be many pilots who fly better than I and many planes nicer then the B-25 ARF, but I'm just saying...

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Fytrjok,

Well I missed getting "down" for Warbirds over Denver, so I / we are all waiting for new B-25J video posts. Did U get a Squadron flight? Won't admit how many times I have watched your 1st pair of '25's video!

1st build Question: with the OS FS-70's did U install with neddle valve / extension Up or Down? Anyone?

Thanks,
aka Lt. I. B. Narly

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Thanks for the reply about the nose gear. I'll look into the fix. Robart seems to think the strut spring is too strong; transfering the stress to the pin. Suggested cutting some coils or installing a softer spring ?????????? They also stated the pin is made of Hardened steel. Look like Hardened steel to you guys ??. Anyway, I ordered a couple of new pins and I'll check out the (secret) fix. Thanks for the help. Dave. It is funny, how Quiet the field gets when the 25 begins to taxi........

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

krproton If I get done with harvest and maybe get a maiden flight in then there mite be a fair possiblity that I may show up in Ohio with my Wing B-25. I may also bring my Wing P-38 also.

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Hi guys !
I made it ! The maid fly is done.

To begin, I unstick a gear door, when getting the plane from my car. Ok, I will keep the gear down for the first flight.
Then, I tried the twinsync to synchronise my engines. But it was pumping, except at idle or full throttle. [:o], and on the ground she was turning left and right at middle power.
I will ask to bill to try to solve the issue. BTW, could someone could point me the page of the installation of a gyro in this thread, in the case I could not resolve the twinsync issue.

So I decided to takeoff and keep full throtle my 2 OS 46AX.
I needed to trim the elevator. It was climbing too much. Then, she started to fly perfectly, not to fast. And the landing with full flaps was a breeze.

Yes this plane made me "ace" because everybody applaud on the field after landing [8D]
It was the first time I saw a RC twin since 30 years.

Great plane ! Congratulations kproton !

I hope TopFlite will produce other twin like the P38.
ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

ML,

Felicitation, c'est un avion extraordinaire et quel bon "feeling"...Well congrats and yes you can find some info on the first few pages of this thread on the gyro installation on the rudder by myself. Easy to fly and impressive.

Bonne continuation!

Normand

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Good luck getting a nose gear pin from Robart.

I order an upper strut and two pins about two months ago, and I'm still waiting. I ended up making a pin out of piano wire and soldering a washer on top. I'm still using this fix.

Ethan

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Thanks normandouellette

Just a little video of this first flight.
http://video.google.fr/videoplay?doc...72806762&hl=fr

am I the only one using a twinsync with 2 OS 46 AX ?

ML

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Well, I'll look for you then (or you look for me!).

Tim

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Congratulations ML!!!

I feel the same as you - when I fly the B-25 it makes you look like an expert even though all you are doing is flying around!!! Not necessarily because the plane flies so well (okay, it does), but just because it's a twin-engine WWII bomber.

Well, get your gear doors and gyro sorted and have fun!!!

Tim

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 

Having looked over the front strut to eliminate the bending pin problem on grass runways.... seems to me the strut is actually too soft, not too stiff as Robart suggested. The strut easily bottoms out when the strut is pushed up when the plane is on the stand. This would transfer the weight and force directly to the pin. The strut should absorbe the shock without bottoming out. Normandouellettes idea of adding a rubber bump stop to the strut is a good idea but I went a little further with my fix. I disassembled the strut, removed the spring and inserted a 1/4" dia. rod a little less than a 1/4" long inside the strut leg under the spring. This slightly compressed the spring when assembled making it stronger. I still get the full travel and is less likely to bottom out. I still have the rubber bump stop on and will let you know how it works out. Dave.