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-   -   Top Flite B-25 ARF (Tecnical, tips, suggestions) (https://www.rcuniverse.com/forum/arf-rtf-75/6494380-top-flite-b-25-arf-tecnical-tips-suggestions.html)

RCGuy41 07-13-2010 12:56 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Mustang Fever, nice nose gear, it should handle any grass field.

Well after my B-25 had sat in my garage for the past year due to other projects; I finaly found the time to fix a few nagging problems, i.e. a striped HS-85 rudder servo gear set, tightend the inner and outer wing panels and add some monokote to the belly just aft of the nose wheel well. Due to to a ground miss hap my fault. All in all, the repairs took less then 8 hour's, the hardest part re-wiring the inner wings. I also changed my props from APC 11X8 2B to 12X7 2B, my engine performance went down with the prop change; I was turning 9700 RPM on two OS AX 46 2S engines.

Last Sunday I took my Bomber to my field and put four good flights on her (sorry no video), the first flight I was very nervous but as I gained my confidence on this big bird my nerves settled down. I now have 20 flights on my B-25 and just love the flight characteristics of this airplane, but noticed one thing after getting everything home, my right engine bearings are starting to feel as if they are grinding, so time to pull the engine and replace the bearings. The other engine is smooth as a babies bottom. I get paid Friday and I will place an order with Boca Bearings for a set for my OS 46 engine.

Mustang Fever 07-13-2010 05:24 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Glad it's going well, Brad.

I have had real good luck with 46AXs turning APC 10x6 props. They'll run all day on 8 oz of fuel, and do about 14,500 rpm on 10%. That's good for over 80mph and about 6.5 pounds of thrust each.

Speedracer2112 07-14-2010 06:44 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
1 Attachment(s)
Anyone want a $50 rebate? Top flite has a rebate on most of their planes.

http://www.bestrc.com/rebate/big-arf-rebate/index.html

Got a picture too!

SR

RCGuy41 07-14-2010 07:45 PM

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

There is a TF B-25 for sale on ebay will be their for the next four and a half days, here is the link http://cgi.ebay.com/Top-Flite-B-25-M...item255be1beda

Thomas B 07-15-2010 03:34 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
I popped the nose gear shear pin a few weeks back and also took out my nose gear door, cleanly. I plan on winding some music wire springs and adding them to normal Robart hinge pins.

Wass pleasantly surprised as the very low cost of the pins from Robart....at that price, was not worth making my own and I ordered one or two extras...and no shipping change for those I ordered plus some other minor spares

djstar39 07-15-2010 07:12 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
I popped my nose pin too a couple weeks ago and ordered 5 spares from Robarts.

Dave

Wyoming Cowboy 07-22-2010 08:42 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Ordered 27 feet of extensions yesterday for this beast...

Speedracer2112 07-23-2010 05:40 PM

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


ORIGINAL: Wyoming Cowboy

Ordered 27 feet of extensions yesterday for this beast...

Really? Are you going to convert it to a controll line? LOL!

SR

Wyoming Cowboy 07-23-2010 09:10 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Nah lol...if you figure all the recommended servo extensions/Y-harnesses it's about 27 feet of wiring.

asnook 08-03-2010 02:44 AM

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

Lost my B25 last weekend :(

Engine out low over some trees, twynsync cut the running engine. Had to open up again to clear the trees and guessed the rong rudder input, death spiral !

Got a new one delivered and will start all over :) Had many great flights but sometimes $$it happens

djstar39 08-03-2010 11:06 AM

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

Bummer!!! My worst nightmare... engine out, low altitude over trees. Sorry about the loss but it sounds like you're back at it with a new one. Admire your attitude!


Ozmodeller 08-06-2010 12:18 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Has anybody fitted or thought about fitting a couple of Saito FG14B gassers, do you think that there would be any problems doing so (apart from the cost)?

Peter

Termites Dream 08-06-2010 06:48 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Peter,
I have the recommended OS FL-70 engines on mine. With retracts and onboard glow I am at about 20 pounds. Takeoff performance is marginal on grass. If you fly from a hard surface, should be fine. Horizon says the FG14 has similar performance to the FA72 glow. You might want to use a battery eliminator to keep the weight down.
David

Speedracer2112 08-10-2010 08:54 PM

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


ORIGINAL: Ozmodeller

Has anybody fitted or thought about fitting a couple of Saito FG14B gassers, do you think that there would be any problems doing so (apart from the cost)?

Peter
"christophe31" had them on his. He lost it secondary to motor failure. He said he was going to rebuild. Search his name to see his posts or look at about pages 95-97.

SR

elojim 08-11-2010 02:22 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
1 Attachment(s)
Hi,

i have the OS 70 FS Surpass on mine. Retracts, wheels with brakes from Glennis, sequencing gear doors (from rcdon). I am at about 21 pounds. No problem to take off from a hard surface but i have to run at less 120 meters. Fly is very realistic.

Mustang Fever 08-11-2010 06:22 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
The numbers on the FG 14 look good for the Mitchell: 14x6 @ 9200 equates to roughly 52 mph and over 9# of thrust per engine. That's almost identical to what I'm getting with 55AXs and 12x6 MAS 3 blades. The MAX 3 blade might work well on the FG14s as well. They definitely look better than two bladers. The FGs are a little heavier, but part of my balancing routine with the AXs included the heavy brass prop hubs. She does need some weight in the nose.

My advice only: skip the retracts and go with fixed until you've flown it, got used to it, and worked the bugs out. You might want to consider a Fults 1/4 nose strut, as these things are tough on the front end wheel.

christophe31 08-11-2010 03:51 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
hi guy's,
yes i've already used 2 FG 14 SAITO gasser, they are well sized for this plane, take a look of my first fly:
[youtube]http://www.youtube.com/watch?v=qiOS5Kheorg[/youtube]
i use one tank for the both motor, in the center of the fuse ( be sure to use for that 2 complete separate fuel line) so by this you can place the ignition in the nacelle just in place of the tanks. i've use too my e-retract too win weight and place too the final weight was 9kg=19.80 pounds .
the fly was good with this gasser, but i've never find how to tune well these motor, they're very hard too set up because they consume too low.....i've crash my B-25 because i've loosing one motor in flight, after that i've buy an 90 trainer too mount these motor to tune them, and too rebuilt the B-25 after having confidence in these motor.
but unfortunatly i havent' succed in that and after many many fly with the trainer and many many shut off in flight, i've sold my both saito's.

may be it's me .... but i've never set up fine these motor.

Mustang Fever 08-11-2010 04:22 PM

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

Too bad about the engines and your B-25. I haven't used anything but OS AX series for a long time, but even those require a good breaking in and fine tuning to get them running their best. I've found that there is a definite "sweet spot", the combination of high and low end needle settings, that each engine can be tuned to, but it takes time, patience, and a bit of experience to achieve. For example, I have a 75AX in a 1/7 Mustang that's inverted, and since I tuned it, will run for 3 or 4 minutes at a 2150 rpm idle and still come back clean to full power.

Speedracer2112 08-11-2010 07:05 PM

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


ORIGINAL: christophe31

hi guy's,
yes i've already used 2 FG 14 SAITO gasser, they are well sized for this plane, take a look of my first fly:

the fly was good with this gasser, but i've never find how to tune well these motor, they're very hard too set up because they consume too low.....i've crash my B-25 because i've loosing one motor in flight, after that i've buy an 90 trainer too mount these motor to tune them, and too rebuilt the B-25 after having confidence in these motor.
but unfortunatly i havent' succed in that and after many many fly with the trainer and many many shut off in flight, i've sold my both saito's.

may be it's me .... but i've never set up fine these motor.
I'm glad you showed back up Chris31. Those Saito gassers are tough. I would call them junk if I wasnt a gentleman. : ) I had bought them and sent them back. My FG-20 was enough pain. It still doesnt run right. Im glad you sold them.[sm=wink_smile.gif]

Os 81alphas! Mine could go for 17-20 minutes on a tank of 15%. I land at 9 minutes for safety. Sound is PERFECT!

SR

Speedracer2112 08-11-2010 07:16 PM

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


ORIGINAL: Mustang Fever

My advice only: skip the retracts and go with fixed until you've flown it, got used to it, and worked the bugs out. You might want to consider a Fults 1/4 nose strut, as these things are tough on the front end wheel.
Respectfully, I have to disagree here. Retracts are tough, I agree there, but the performance of the plane with the wheels up is SO NICE that it is well worth the challange. I did have my learning curve with them but it was worth it. With the gear down I loose 10-20 MPH. Just learn to land on the mains and you will do fine. I wouldn't do it any other way. We may have to start a poll?

SR

christophe31 08-12-2010 12:16 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
a french guy, called me because he know by forum that i've bought FG14, he had the 20, and have the same problem than me: no way to set up correctly.
If i've bought gasser for that plane it's about the reliable of all gasser motor, but i need to tell that these motor can't do that.
I've found in germany 15cc gas in 2 stroke, when i have some time, i'll ordered one and try it.

lfierro1 09-06-2010 08:24 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
i have had my b-25 ready sinse christmas but just got around to flying it. great flying plane but my nose gear is bending on very soft landings. anyone got a fix for me? robart gear by the way.

djstar39 09-06-2010 08:31 PM

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


ORIGINAL: lfierro1

i have had my b-25 ready sinse christmas but just got around to flying it. great flying plane but my nose gear is bending on very soft landings. anyone got a fix for me? robart gear by the way.

Mine haven't bent... it just snapped clean off and took the gear door with it! [:@] Landing was on grass so no other damage. Replaced the pin. Robart claims they make it this way to avoid shoving the entire assembly through the cockpit on a rough landing. I know folks have replaced the pin with a non-Robart self made pin or heat treated the Robart pin.

I need to get mine up in the air again soon... A lot of wind in Indiana lately. Great flying plane though!!

djstar

RCGuy41 09-07-2010 06:50 AM

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


ORIGINAL: lfierro1

i have had my b-25 ready sinse christmas but just got around to flying it. great flying plane but my nose gear is bending on very soft landings. anyone got a fix for me? robart gear by the way.

lfierro1,

I love the way my B-25 tqakes off, very scale and fly's like a giant trainer. As for your nose gear, you are performing a flair before touch down and if on grass try to slow down further if possible. If you three point the plane, you will put too much stress on the nose gear and as you have found out it is bending and others have had the gear snap. Call or e-mail robarts and order atleast two more nose gear pins and if you know how to heat treat to strengthan the pin, do so.

Mustang Fever 09-07-2010 08:23 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
1 Attachment(s)
After having two planes with retracts, and spending more time messing with retracts than flying and having fun, I put fixed gear on my B-25. The mains are very tough and trouble free. This is what I used for the nose gear, which was too skinny and bent on almost every landing:

http://www3.towerhobbies.com/cgi-bin...&I=LXH133&P=ML

It is trouble free and when you use it, you'll need almost no weight in the nose to get the CG correct. All that's necessary for installation is to drill the plastic gear block and the tiller bar out to 9/32.

I have made some terrible landings with this aircraft and had no damage to either the gear or the structure supporting it. Robart is full of it. Their gear is simply not strong enough for this application, and they should do it over or pull it off the market.


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