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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)

k4nkc 12-07-2008 10:49 AM

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

Top Flight B-25 ARF All Parts w/ 2 Magnum XL91RFS Four Stroke 91s
Going,going......
http://cgi.ebay.com/ws/eBayISAPI.dll...m=190270684574



toreo 12-08-2008 01:48 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
1 Attachment(s)
I flyed on FL70 one season. Fl-70 is good choice power engine for TF B25. Except 1 thing. Sound. This engine does not reliable work with pump without muffler.

Now i sold my engines and start to pumping up my B25 :)

norm 12-08-2008 10:24 PM

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

I hate you for doing this!! Those are my engines!!! .............................

Nevertheless this is the best choice of engines and it will sound crazy. Good choice T
oreo, and I' m looking forward to hear it fly.

The Hockey trip in Russia (octber 23 to Nov 2 ) was amazing. Great country Russia and mostly the women...I was also in Helsinky Finland and then a cruise to Stockholm, we got wiped all the way but most of our players slept 10 hours in ten days total.

I visited the War Museum in Sankt-Petersburg and the 55 feet rocket was made in 62 the year I was Born, very impressive. You see Me with the coach of Sankt-Petersburg First Division Hochey team ( my eyes are off the socket, too much Vodka), his boss owns lots of ships and milions of dollars. Glad I'm back with my wife. The first thing I did was to buy her the classic Russian high heel black boots and tight jeans..(LOL)

Normand

RCGuy41 12-09-2008 08:17 AM

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

Glad you were able to enjoy your trip and the sportsmanship the Canadian team showed, some great pics thanks for posting some. Since you are building a Lancaster over the winter, do you need an escort? Currently I'm build a TF Spitfire and posting my progress under "Kit building" here on RC Universe here's the link http://www.rcuniverse.com/forum/m_7785865/tm.htm it was started by another gentleman, since the down turn of the U.S. economy "Starcop" has not been able to work on his Spit. I still have alot of work left to do before the wings are complete. By spring I should be ready for her maiden flight.

At this point in time my B-25 is down due to "DOG DAMAGE" needless to say we no longer have that DOG, with Christmas and my Spit build and my wifes honey do lists, decorating, my B-25 has been collecting dust. If things weren't any worse our local hobby shop here in Southern Maryland has closed their doors, affective 6 Dec. So fuel and spare parts will have to come from the internet "Tower" or some other sight, but at least there's another hobby shop an hour's drive north of us to purchase fuel.

Brad

toreo 12-15-2008 05:02 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
1 Attachment(s)
Hi Normand!!
Nice trip!
I think 100T is not best choice. I think, Rcdon was little right, when choice 90TS. Less weight, less vibration, only one needle on right place.
absolutly best choice- radial 90!!! Lets do it, Normand!!!

In the same time when you was in Russia, i was in Germany. I absolutly impressed of their Techinical Museums. And beer, offcourse :)

sharpnr 12-16-2008 07:32 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Hi, I've just ordered the TF B-25 and am trying to figure out what engine to install. I'm leaning towards the O.S. 81 cause it has the same mount area as the O.S. 70, but see some are running the Satio 82. I could use some ideas for this one! Thanks

Quigleywins 12-17-2008 06:21 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
G-day Sharpnr I have a set of OS81 on my 25 they look great and fit with 90deg bend on the exhaust so the gas flows out down the other side with no cutting of the cowls for the exhausts. I have never started the 81s but I do keep misplacing the small woodruff keys out of the cranshaft ,you know prop on ,prop off, cowl on prop on . O bugger wheres the key it was there one second ago.

krproton 12-17-2008 07:58 PM

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

I wish the 70 S II's were still available. That was the PERFECT engine for the B-25. But I know many have had success with the new FL 70 as well. I am building a new B-25 using the O.S. .81s. I haven't yet flown a B-25 with these engines. With the .70's, I was running the Master Airscrew 12 x 8 3-blade. This was the best 3-blade (of the ones I experimented with), but I think the .81 will pull this propeller even better.

Also with the .81, I will be using the exhaust pipe from the .70 Surpass because this will locate the muffler perfectly in the molded-in "divet" in the fiberglass nacelle. However, this required slight trimming of the engine mount and turning the mount to a new location.

Of course, I have also read several accounts of great performance with the Saito as well! :)

Here are some photos....

camdyson 12-18-2008 01:01 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Hey, that's the ARC version I want - not fair!:(

C'mon Tim, I'd love to do another with 3/4 oz glass and panels/paint. Any chance they'll change their minds?

Cam

norm 12-18-2008 04:17 PM

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

Here is some info on engines, I am still convinced that the FA100T is the best choice for this plane, besides the 90R3 is an absolute No No for the simple reason that the power output is only 0.75HP!, it is simply not powerful enough. I own one and it sounds nice on Idle and that is all. It is unable to "positively" pull a plane...I have it installed in a Sopwith Camel (double wing able to lift an encyclopedia) and fly like @#$%*&^%$ to say the word.

The FA100T develop 1.6HP according to Saito vs the FA90TS that develop 1.0HP. You gain 0.6HP ovet the 90 and once you set the 2 needle valves you have a great performer. There is a definite advantage to have a seperate needle valve per cylinder because multi cylinder engines never burn equally. I have experience with the FA200Ti, the FA90R3 anf the FA450R3, all multi cylinder and each cylinder burn unequal amount of fuel...some lean, some rich and only one good....

Nevertheless those engines are spectacular and having a multi engine is always a good thing. You can set your FA100T by tuning each cylinder to a good "ear tuned" setting and fine tune with a thermometer (probe type) to check each cylinder head temperature / exhaust gas temperature to obtain peak temperature setting and then rich the mix by 1/4 turn to cool temperature and maintain peak poerformance. Once you have this set up it is very rare that you will have to play with the mixture again. You do the same with the idle mix setting. Good luck with your engine and I stay tuned to hear this.

Normand



krproton 12-20-2008 11:47 PM

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

ORIGINAL: camdyson

Hey, that's the ARC version I want - not fair!:(

C'mon Tim, I'd love to do another with 3/4 oz glass and panels/paint. Any chance they'll change their minds?

Cam
Hi Cam. I feel your pain - I do. And I suppose there could be a chance, but whether or not they decide to come out with an ARC version is out of my hands. I think right now your only choice is to buy the ARF and strip the covering. That may not be very appealing to you, but I've done this with several ARF's and they always come out great. Problem is, with the B-25, there's a lot of paint as well - and much of it on framework over clear plastic (which would be tedious to sand).

All I can do is send my (and your) wishes "up the chain" and hope. [sm=72_72.gif]

camdyson 12-21-2008 07:15 AM

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


ORIGINAL: krproton


ORIGINAL: camdyson

Hey, that's the ARC version I want - not fair!:(

C'mon Tim, I'd love to do another with 3/4 oz glass and panels/paint. Any chance they'll change their minds?

Cam
Hi Cam. I feel your pain - I do. And I suppose there could be a chance, but whether or not they decide to come out with an ARC version is out of my hands. I think right now your only choice is to buy the ARF and strip the covering. That may not be very appealing to you, but I've done this with several ARF's and they always come out great. Problem is, with the B-25, there's a lot of paint as well - and much of it on framework over clear plastic (which would be tedious to sand).

All I can do is send my (and your) wishes "up the chain" and hope. [sm=72_72.gif]
It would be nice. Especially when you consider all the mods we (well, some of us!) make like bomb bay, cutting up gear doors, wing lights, rivets etc, it would be alot easier to end up with a nice "finished" look if it got painted all in one hit at the end.
Ah well, better wear the current one out first............

Merry Christmas to you all,

Cam


toreo 12-21-2008 04:35 PM

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

ORIGINAL: normandouellette

Hello Toreo,

Here is some info on engines, I am still convinced that the FA100T is the best choice for this plane, besides the 90R3 is an absolute No No for the simple reason that the power output is only 0.75HP!, it is simply not powerful enough. I own one and it sounds nice on Idle and that is all.
Normand
May be... But i flyed on B25 with FL70 (1.1 hp) at 2/3 throtle almost all time...

How make rivets on monokot ?
Thanks..

camdyson 12-21-2008 05:01 PM

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


ORIGINAL: toreo


ORIGINAL: normandouellette

Hello Toreo,

Here is some info on engines, I am still convinced that the FA100T is the best choice for this plane, besides the 90R3 is an absolute No No for the simple reason that the power output is only 0.75HP!, it is simply not powerful enough. I own one and it sounds nice on Idle and that is all.
Normand
May be... But i flyed on B25 with FL70 (1.1 hp) at 2/3 throtle almost all time...

How make rivets on monokot ?
Thanks..
See Tim's build early in the thread for rivet technique on Monocote - used "Rosie the Riveter" system.

norm 12-21-2008 07:38 PM

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

Normand

Mirco 12-23-2008 08:30 AM

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

A few updates: firewalls painted with epoxy, scale details done, decals done, rc stuff and air kit for the gear installed.

Pilots, rear gunner and prop nuts still missing and the CG has to be balanced.

happy XMAS

regards

Mirco

Mirco 12-23-2008 08:40 AM

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

watch this: B-25 flying display Breitscheid (Germany) 2008

http://www.clipwings.com/index.php?c...o&video_id=308

regards

Mirco

krproton 12-23-2008 11:54 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Looking good Mirco. [sm=thumbs_up.gif]

Keep us updated. Can't wait to see it fly (or flying photos!).

Tim

Steve in Denver 12-26-2008 10:27 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Micro... Thanks, beautiful clip.
I decided to learn how to fly the real thing before I build one. So I'm building a flight sim, complete with "Briefing Time" software and a brand new surround sound system, yokes, pedals, the whole nine yards. At least my grandson can sit in my lap and fly this one...lol.
Steve

Mirco 12-27-2008 03:01 AM

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

In real live, I fly this one as an member of the German Air Force.:D


http://www.clipwings.com/index.php?c...o&video_id=260

regards

Mirco

flaviosi 01-01-2009 06:08 PM

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

DO NOT follow the directions from Top Flite on the Electric conversion of the B-25. I followed that conversion to the letter. On the maiden flight I ran through all the runway, took off on the limit. The plane took off softly with almost no lift. I was able to turn, fly-by over the field but on the next turn, even trying my best, the plane stalled. I lost it behind a building, cut off the engine. By a miracle, it broke some minor stuff and one of the rudders. I couldn't help myself not being very angry with Top Flite suggesting such a lame conversion. 5s is simply not enough power to sustain flight with the recommended 14 x 7 Master prop. I believed and got screwed. Take my advice and don´t make the same mistake.

Well, I'll reconvert it to glow and I'd like some strong advice on what engines to use. Please, help me. Help me good! :)

Thanks,

Flavio

norm 01-01-2009 06:29 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
That should teach you flavio!

Now get some glue, fix that beauty and get yourself a pair of OS 81's or Saito 82's and a pair of MAS 12 x 8 3 blade. Both those engines will fly this plane with muscles. Electric motors are good but there is no character to e-power in a warbird. Get some V-30 pumps, throw away those mufflers, go straight pipe and get those loud obnoxious engines running and you will get excitement, attention and applaud for your next flight.

Anyways Flavio, nice to hear from you again. Hope the weather is nice and warm down there in Brazil. Here in Montreal we got a chilly -30C degrees.

Happy new year and get this thing back on track.

Normand

flaviosi 01-01-2009 08:03 PM

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


That should teach you flavio!
Well, it did. I tried something different. I even installed that sound simulator. It´s real cool. It even has a machine gun sound. But unfortunately the electric engine and batteries screwed things up.


I'm really glad to hear from you on this Jan, 1st!!! Specially because you're the same positive, nice and kind guy as always! :) Thank you for your kind words!! I wish you everything in double!! Hopefully 2009 will touch you with health, peace and wealth.

I'll definitely get this thing going. However,


Get some V-30 pumps, throw away those mufflers, go straight pipe
You lost me here! V-30 pumps? Where do I get them? What are they for? straight pipe? By straight pipe you mean no muffler and just that small pipe that comes out of the exhaust? Wow! That sounds great!!! What engine is your favorite? (I'll have to buy either of them). Should I use a twin glow igniter?

Wow! It's gonna be really exciting!

Flavio

norm 01-01-2009 08:54 PM

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

VP-30 replace the muffler pressure and is simply a pump activated by the breather. No muffler is cool since you do not have that big metal thing sticking out. My favorite is really the Saito 82 or the FA 100T engine but the OS 81 has a good advantage, less messy, and just as powerful. Anyways they are probably the top picks for that plane, anyone of those and you make a good choice in my opinion.

The VP-30 is a perry pump, here is the link: http://www.perrypumps.com/prod02.htm

As far as a twin glow igniter go with the Mc Daniel MCD472TE from sonic tronic, call direct as they do not sell this model in hobby shop talk to Hank or e-mail him: http://sonictronics.com/xcart/home.php?cat=422

Have a good one as well Flavio and keep in touch!

Normand

flaviosi 01-01-2009 09:22 PM

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

Thanks for the tips, pal. If OS is less messy, I'll go for it... :) I'm ordering the stuff and start to get the darn thing going... :) What other foruns are you hanging around, Normand?

Flavio

Quigleywins 01-06-2009 07:58 PM

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


ORIGINAL: flaviosi



Thanks for the tips, pal. If OS is less messy, I'll go for it... :) I'm ordering the stuff and start to get the darn thing going... :) What other foruns are you hanging around, Normand?

Flavio
I fitted the OS81 they fit perfect and with the 90deg exhaust bend fitted the exhaust exits on the other side very neat with no extra cutting of the cowls for the exhausts. Rocker covers and prop nuts neaded to be removed to install cowls .
PS. Try not to lose the woodruf key in the crankshaft. They fall out so easy.
Yours Paul T

CCFPILOT 01-06-2009 11:49 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
put some blue locktight on the woodruf key, works great. This tip from the "Oily Hand" in RC Report Mag.

Mirco 01-07-2009 03:40 PM

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

First: nothing new

Still waiting for 2 Lipos from hobby city, pilots from UK and fuel.

BTW. First engine run is not possible without fuel an temperatures below -10°C (the engines and no fuel are not the problem, but I am, brrrrr)

regards

Mirco


CCFPILOT 01-08-2009 04:50 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Does anyone know where the four 3/8" X 12" foam wing seating tapes are used?? Top Flight Technical Help says "the tape is used to put the wings onto the fuselage. Thanks." This must just be a bonus, as no tape is required on the wings of this model. Could go under the stab? No, I don't think so.

rnordeck 01-08-2009 06:43 PM

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

Yeah, I scratched my head on that one too. But, it's there on P. 21, #13. I found it after I had already applied fuzzy sided velcro pads!!

My build tip for the day: Order a package (or two) of #0 X 3/16 Button Head screws (STP0003B) from http://microfasterners.com. Work great for attaching top turret, canopy, nose and side waist gunner windows and the wing top carb intake fairings. Note that U will also need a tiny .035 Hex Key (BL02).. I also ran out of #2 X 3/16 screws so consider 'nother hundred black #2 X 3/16 (STP0203B).

BadBob

norm 01-08-2009 08:59 PM

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

the btape go on the styrofoam stand supplied to sit the plane...2 on each stand...the instructions are clear on that!

Normand

harleydoberman 01-14-2009 08:01 PM

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

I have assembled the b-25 as per instructions with two OS 81 engines and robart retracts. When I balance at the 5" cg point with retracts down I am still slightly tail heavy with 3 oz of lead in the nose, but with the retracts up up the plane goes nose down very slightly. As I am new to planes of this size with retracts could you tell me if this is normal. I have a 4700 suc c NIMH battery in the cockpit behind the piolt seats. I would be greatful for any info.

Tony

Thomas B 01-14-2009 09:16 PM

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


ORIGINAL: harleydoberman

Tim

I have assembled the b-25 as per instructions with two OS 81 engines and robart retracts. When I balance at the 5" cg point with retracts down I am still slightly tail heavy with 3 oz of lead in the nose, but with the retracts up up the plane goes nose down very slightly. As I am new to planes of this size with retracts could you tell me if this is normal. I have a 4700 suc c NIMH battery in the cockpit behind the piolt seats. I would be greatful for any info.

Tony

I always set the CG with the tanks empty and the gear down, as that is how it could be landing....:) I would put it right on the CG with gear down and empty tanks and let it be a little noseheavy when the gear is up and there is fuel in the tanks.

CCFPILOT 01-14-2009 09:22 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
If you can, mount the battery under the nose gunner as per the manual. I have a 4200 mA battery mounted there and it balances with no extra weight.

jdhughen 01-15-2009 02:43 AM

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


ORIGINAL: harleydoberman

Tim

I have assembled the b-25 as per instructions with two OS 81 engines and robart retracts. When I balance at the 5" cg point with retracts down I am still slightly tail heavy with 3 oz of lead in the nose, but with the retracts up up the plane goes nose down very slightly. As I am new to planes of this size with retracts could you tell me if this is normal. I have a 4700 suc c NIMH battery in the cockpit behind the piolt seats. I would be greatful for any info.

Tony
I'm not understanding this situation... I'm completly the opposite. Gear down brings weight forward and makes the nose heavier not lighter ( I'm using robarts with scale dubro tires/wheels) . I went with Norman's suggestion and balanced with gear up and let it go nose heavy with gear down. The last thing i want is a tail heavy aircraft. ??? that fuel tank location puts most of the fuel on the CG so it's a non comcern. My $.02

Joel

harleydoberman 01-15-2009 11:21 AM

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

If I explained it right you might understand better. I wrote it the opposite. I balanced it with gear down (as per the instructions) and it is still slighlty nose heavy because when the gear goes up up it becomes slightly tail heavy. If I balance it level with gear up it wants to take a nosel dive with the gear down. I hope that explains it better. Is that normal and should it bal perfect with gear up or down? I would think that I would want to be balanced in the flying mode (gear UP) but that means a mushy aircraft nose heavy with gear down. Will the flaps comensate for this? Any thoughts would be helpful.

Tony


PS
I hope I explained it right this time!

krproton 01-15-2009 07:34 PM

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


ORIGINAL: harleydoberman

Tim

I have assembled the b-25 as per instructions with two OS 81 engines and robart retracts. When I balance at the 5" cg point with retracts down I am still slightly tail heavy with 3 oz of lead in the nose, but with the retracts up up the plane goes nose down very slightly. As I am new to planes of this size with retracts could you tell me if this is normal. I have a 4700 suc c NIMH battery in the cockpit behind the piolt seats. I would be greatful for any info.

Tony
Hi Tony. I wrote a detailed explanation about this before. You can find it in an earlier post. In short, yes, the C.G. will shift from where it is when the gear is extended to where it will be when the gear is retracted. However, we have accounted for this in our testing and in the specifications of the C.G. location in the instruction manual. We could have told you to balance the model with the gear retracted, but then we would have moved the recommended C.G. location aft accordingly. Balance it with the gear down as instructed in the manual.

Good luck with your plane and keep us updated on how it is going. Shoot us some pics too![sm=thumbup.gif]

Tim

harleydoberman 01-15-2009 09:12 PM

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

Thank you for reitterating what you already posted. I looked to find info about cg but it is a large post. I have moved the battery to the front of the fuse and removed the nose weight, so now I need a little tail weight. I will balance the model level with the gear down and when the gear goes up it will appear to be tail heavy but that is okay. I hope I have understood this correctly.

Thanks for the help

Tony

krproton 01-15-2009 10:55 PM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
No sweat Tony.

Actually, I looked for the post too, but after going through about ten pages I gave up. I did a write up about it for a customer back at work a few months ago. If I remember, I'll dig it up and post it tomorrow.

As I recall, most of the prototypes I worked on, and my own personal B-25 I got from production stock also required a few ounces of tail weight, so I think you're right in there.

Yes, you have understood it correctly. Again, we could have specified balancing the model with the gear up, but then we would have moved the C.G. back accordingly. If, for example, the C.G. shifts 1/2" aft when you retract the gear, we would simply have recommended a C.G. 1/2" farther aft then it is now. And again, we test fly the model in all imagineable configurations - gear up, down, full fuel tanks, near-empty fuel tanks, etc. Before we even test fly a model, we note on the workbench how much weight it takes to shift the C.G. to predetermined locationsus -ually in 1/4" incriments. At the field, we then find the outer limits of the C.G. by flying the model at each of those locations until it performs adversely, thus establishing the forward and aft limits (of course, control throw comes into play as well).

Best of luck! ;)

Tim

camdyson 01-16-2009 06:43 AM

RE: Top Flite B-25 ARF (Tecnical, tips, suggestions)
 
Look around post #:425 for CG discussion.


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