RCU Forums

RCU Forums (https://www.rcuniverse.com/forum/)
-   ARF or RTF (https://www.rcuniverse.com/forum/arf-rtf-75/)
-   -   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)

timothy thompson 10-31-2007 11:27 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
EMS JOMAR google it and the site come up its elecronic but can be used to operate a sevo to actuate a second spool valve and small tank. i wouldnt want to use one tank for all the sequencing. I know people are saying we are adding weight but i only will a a pound or two in detailing

krproton 11-01-2007 07:15 AM

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

Don't stay up too late!

It's difficult to say if the plane handles much different with the doors open vs. closed. Whenever I extend the gear, I always slow the model first anyway, so it's already going slower. The flaps are extended as well, thus adding more drag and changing the model's configuration even more.

Yes, you cold add the air cylinders and sequencers to operate the doors and close them after the gear has been extended, but this would require splitting one of the doors into two pieces (you would then have three doors!) and greatly add to the complexity and expense (gee, why am I reciting what I have already written in the first page of the manual!?[:@]). In R&D, we have to remember who our customer is--somebody who wants to get something in the air relatively quickly at minimal/reasonable expense. Adding bomb bay doors and sequencing gear doors would defeat our mission. But again, it's a free country and anybody can add any extra details they desire![sm=teeth_smile.gif]

Let us know how your maiden flight goes.

I've lost track of who is going electric and who is going glow. If using glow, BE CERTAIN you have adequately run and tested your engines and are confident in their performance. [sm=devious.gif]


krproton 11-01-2007 07:17 AM

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

ORIGINAL: timothy thompson

krypton i see you cut the cowls. im running 2 4s 5000mah in series so 8s 5000mah. batts are through the bomb bay hatch.I hope two batts will run both escs and motors. They are rated up to 8s so we will see. im very impressed. it would make a fine kit too bad you dont offer it as a kit!

hey im 47 and not old
Hi Timothy!

For the record, I had nothing to do with the electric instructions posted on our web site.

mike-rc 11-01-2007 07:44 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
1 Attachment(s)
I was having trouble with the outboard door not closing all the way. I finally realized that the clevis on the lever interferes with the end of the air cylinder. The lever moves down flush with the cylinder. I changed to a ball link leaving the back of the lever flush and now it works. I also found a problem with the 5" dim out from the firewall. I had to go to 4.65 .[img][/img][img][/img]

norm 11-01-2007 09:43 AM

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

Improvements...no, only add on.

You are right about marketting research, your customers are exactly what you mentionned. Let me inform you of my impressions and I welcome anyone thinking the same way to join me, This B-25 is extremely well built. Of course it is an ARF and unlike most arf's out there, this one enables you to go further in detailing. Primarely because of the quality of construction, example: the nacelles are nice and sturdy and will permit mod's such as installing air cylinders. The whole aircraft demands no reconstruction in order to improve it. It is interesting that some of us may whant to go further and improve this model without compromise other then the $ we decide to put in it. With or without electric windows, for guys our age this may make some sense...but even without those nice features you can still fly a great model and that is interesting! I got to say that Top Flite and the whole team has made a superb ARF and this B-25 is really happening these days and for this you deserve a good round of applaud.

And my opinion for any one going glow,

Yes the glow engines needs to be well tuned and again if you know a good "engine tuner" have him help you. Check for 1) good pick up after 1.5 min idling. 2) clean residue coming out of the muffler, 3) tune the engine full throttle with 1/4 tank and reduce 100-200 rpm rich on the high speed valve. Follow instruction manual for setting of low speed needle valve. check the behavior of the engine with full, 1/2 & 1/4 tank.

The tank is slightly large for 70's or 82's and with muffler pressure you may run rich to lean in a longer period of time so make certain that the engine behave properly in all modes ie; full 1/2 & 1/4 without the "I'll take a chance" attitude . If you cannot find the perfect setting like me, then use a pump and you solve the problem. The pump requires more parameters to set it but once it is set it will remain that way. The advantage of the pump is that it will give you optimum performance from begining to the end of the flight and from flights to flights.

Hellcat716 11-01-2007 10:47 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
That is exactly why I am using the YS 63. It has a pressurized fuel system.

krproton 11-01-2007 11:04 AM

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

Ken Isaac who is writing a review on the Top Flite B-25 for R/C Universe had discovered an error in the instruction manual--I suspect, by now, others may have already noted the error, but this is the first I have heard of it.

I listed the incorrect Air Control Kit for the Robart retracts--the pressure tank that comes with the air control kit listed in the manual is too large and will not fit in the nose of the model where shown in the manual. Instead of ROBQ2305 (157VRX Large Deluxe Air control Kit), the correct number should be ROBQ2307 (188VRX Standard Deluxe Air Control Kit) which contains the small pressure tank.

For those who may have already purchased the large pressure tank and prefer to use it anyway, it could be mounted inside the top of the fuselage behind the cockpit. The part number for the correct, small pressure tank alone is ROBQ2372 (#172 Small Pressure Tank).

We apologize for any inconvenience this may have caused. If the package is still unopened or unused and you still have the container and header card, you may contact the place of purchase for an exchange.

Tim Lampe

rcmorrow 11-01-2007 12:00 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Hi Timothy, I was just catching up on the thread.......I have been out of the lop here for a day or so with the halloween celebrations here (I have 2 young children that are starting to enjoy Halloween now).

You may want to think about your battery choices here pretty carefully. I think if you are running the Axi motors on 8s configuration you will want to have a total capacity (all battery packs tied in parallel 8s) of at least 7000mAH to 8000mAH. This would mean each 8s pack arrangement (2 8s packs for the plane) would have at least 3500mAH capacity, and then tied to eachother in parallel to give you 7000mAH or more.

I think the information added to the Top Flite website shows they were using 3200mAH packs. Tied together for both motors would make a 6400 mAH pack. I think they were suggesting they were getting 8-10 minute flights with reasonable throttle management (use your own interpretation of what this means).

If you go with your pack arrangement of 8s 5000mAH pack to drive both motors I think your flight times will be limited to about 4-5 minutes maximum, giving some latitude for extra power left if you need it for emergency use.

I also wrote in an earlier part of the thread about using 1 pack to drive both motors. Take a look back and see what you think.

I will be using the E-Flite motors myself since I already have one of them in my supplies. In my case I will be using either 6s or 7s packs tied in parallel. The individual packs will be at least 4500mAH to 5000mAH, tied in parallel will be 9000mAH to 10,000mAH. This should be an effective capacity for flight times of about 10 minutes plus or minus, giving reserve power left in the batteries for emergencies. I will be tying my batteries in parallel and using this as one large pack to drive both motors. The reason I am using it as one pack is to have both motors either running or not running at the same time, thus I won't have a motor out problem while flying.

Hey, 47 isn't a bad age..........I am 46 now and it won't be long till 47 !

kochj 11-01-2007 12:00 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
I believe there was instruction in a Man magazine discussing twin engines.
DOes anyonw know how to mix with there radio, when trying to turn (while ont the ground)
to have one engine speed up and the other not to???? to coenside with which way the rudder goes?
EXp.... Turn rudder to turn left, and the RIght engine increased it's speed to turn sharper?
Or Turn RIght and have the Left engine only speed up to trun right quicker????
ANd then sut off one in the air????????????//


norm 11-01-2007 01:09 PM

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

Please sleep on this one and hope it is gone when you wake up! Don't make your life miserable with all those mix!!! Keep it simple stupid KISS. full scale do not even do this. The only time you may whant to have an engine reving faster is to help turn on the ground only when taxiing and only if you are over 5000-250000lbs other than that you will do fine with one setting. For the rudders you need sometimes to mix a little amount 10-15% mix of rudder into the aileron to maintain the aircraft coordinated in a turn. On a model it is neglectable.

To simulate engine failure you need to program a mix and slave an AUX channel to the throttle. When you activate a programmed switch you may idle the slaved channel and reduce the power of this engine to idle until you turn the switch back on to regain control on that engine. This is desirable to test the airplane behavior and learn on how the aircraft will behave in different attitudes and settings loike in a climb, descent, full power...

Please do not test this with your B-25, get acquaited with the twin star or the Dual-ace and see how those less expensive in time and money planes behave, and most importantly how you behave! Remember keep it high when practicing those manoeuvers, you whant to land and not pick up your model.

Good luck

timothy thompson 11-01-2007 01:25 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
morrow ill try it with the two. electricalc said 10 minutes. i can always order two other packs and run each side seperate with 8s 5000mah or 7s 5000. the motors and esc are rated for 8s so i wont hurt anything. with all my superdetailing i may want more batts

lots more bomb bay work ill upload pics tomorrow pm now have to scratch the bombs this is what modeling is all about

mobyal 11-01-2007 03:48 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Great thread....
Even tho I'm getting the H9 B25 I enjoy reading this one...

flaviosi 11-01-2007 04:45 PM

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

Even tho I'm getting the H9 B25 I enjoy reading this one...
Even though my personal contribution to the thread is quite humble, I'm very glad to hear that.

I'm sure Tim (Krypton and Othy), Mikes, Normand, P39 and the other guys will feel the same.

Particularly, I think it's real odd the way the ideas grow and improve along the thread.

Good luck on your Hangar 9's B-25.


KenVC 11-01-2007 11:07 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
If anyone reading this thread lives any where near Morgan Hill,Ca. a B-25J has been parked at the airport there for the last two weeks. The guns have been removed but other than that all is original. The tail numer is V7. I hope to go by and take some pictures when I go through there next week.

mike-rc 11-02-2007 07:31 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Does anyone know a good technique for putting panel lines on monokote? I would like to scribe them or something like that. I do not want to just take a fine marker and draw them.

KenVC 11-02-2007 08:01 AM

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

Thanks for your continued posts on your build. I also am using 2 Saito 82's. I read your posts regarding using the Perry pumps and no muffler. I haven't recieved my plane yet so am curious. Is there sufficient room for the pumps? With a Saito, did you tap the crankcase for pressure or where did you get your pressure? I sure would like to keep the cuts in the cowls to a minimum. Do the heads protrude out of the cowl?

flycast 11-02-2007 09:30 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Hi Tim,
Appreciate the time you have taken for imputting suggestions towards the build of the B25 this will be a great forum.
I have ordered the B25 placed on a back order from Tower Hobbies at the time availabilty was mid October so I ordered robarts 2 OS FS 70 surpass and a few other bits towards the kit.
Received all the order except the B25 which as I said was due mid October then Tower Hobbies changed it to late October now it's late November!!!!
I emailed Tower expressing my concerns and that I wasn't very happy they replied with complete indifference on what I would assume "take it or leave it" attitude.
I live in the UK and sometimes it's not easy to get info.
Topflite produce great kits I already have bought their Cessna 310 which looks and flies great.
Reading your posts and other members they appear to already have the B25 is there another supplier that I have missed out on?
If you could kindly inform me if there is another supplier I would greatly appreciate otherwise will have to stick with Tower and hope that some time in the future the B25 will be available from them.

kochj 11-02-2007 09:40 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
I actually didn't mean to shut one engine off in the air....
I guess it read that way though, now that I have looked back on it....
It should have read... "then turn the MIX off when you don't want it on, line when you are flying" Not to turn the engine off in the air.... LOL

Thanks for the response though....

I believe real planes speed up one engine to turn quicker? Like on a dual engine boat/yaught??

KISS..? HMMm now that is a good concept that I should take to heart!!
I always over think and over do every thing!!
I would finish these planes in such shorter time if I had the KISS in mind....
As most know though it is hard to change old habbits....

krproton 11-02-2007 10:50 AM

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

I wrote a detailed PM to you adressing your questions regarding the next shipment and availibility of B-25s, but the site said you do not receive PM's.

So, here's the short version or what I already wrote;

We have a shipment of B-25s waiting in our warehouse for decals. The decals should be here next week, then the kits will resume shipping. If you have a B-25 on back order at this time, I speculate you willl get one from this batch.

Regarding other sources you asked about, is there a hobby shop you patronize? Perhaps you could inquire with them.

I'm sorry for the delay. I'll try to remember to post when the decals come in and when the kits resume shipping.


alans 11-02-2007 12:39 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
I live in the uk and have a B25, drop me a mail with your Email and I can give you some advice.

kochj 11-02-2007 01:56 PM

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

ORIGINAL: mike-rc

Does anyone know a good technique for putting panel lines on monokote? I would like to scribe them or something like that. I do not want to just take a fine marker and draw them.
check out the link
These are some good ideas to try...
They have wrked quite well for people....


mike-rc 11-02-2007 03:01 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Thanks for the help Justin.

timothy thompson 11-02-2007 07:38 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
im prepainting 1/64th chart tape and applying that. the entire model will have a matt clear spray. i found out the type of incedniary bombs were the M7. Easy to make

Jon Wise 11-02-2007 07:46 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Mike, Do you have any of the gear door arms left? I would like a set if you do. I can mail you a check tommorrow. Thanks Jon Wise

rcmorrow 11-02-2007 08:05 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
Timothy, I found a website of photos that seem to have some very good bomb bay pictures if you still need more:


It is a webshots site with pictures the the B-25 "Killer Bee", I think it is a B-25J if I am not mistaken.


All times are GMT -8. The time now is 08:07 PM.

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.