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

tim the e guy (me had the post pulled) its confusing with 2 tims. You could loose a nichrome in a plug and have the same issue. which is more reliable? IM NOT STARTING ANYTHING JUST ANSWERING YOUR QUESTION

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

S'o.k. Tim - I was only pulling your chain about the engine out. Sorry to hear about you wife's condition btw, back problems are the pitts.

Couple more notes re construction. When mounting the nacelle covers there's a bit of room for error side-to-side, I found the notch for the (extended) gear legs was a good reference to get them aligned. Also, the main tyres (Robart 4" with foam inserts) fouled the oleos on compression. A spacer between wheel and strut helped, and doors still close over slightly offset wheels.

That Great Planes dead-centre gizmo is GREAT too - don't know how I would have mounted the nacelle covers without it. (I'll send you my bank details for the commissions krproton..:D)

Cheers,

Cam

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

on the tf web site they show a addendum of mounting a larger air tank to the top of fuse instead of up front Could some one tell me if the brackets came with kit if so mine were left out and ill have to call tf tomarrow to see if i can get them THANKS

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

I think the large air tank brackets mentioned in the addendum are not included in the kit. The addendum has the template included so you can cut your own out of ply.

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

You can still install the reccommended smaller tank in the nose as per instructions. The larger mounts came about after an error was made in reccommended tank size - so some of us bunnies who got the bigger tanks could still use them rather than exchanging for the smaller ones.

Yep - cut them yourself from scrap ply using the provided templates to suit your tank.

Cam

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

About the tank,

I simply glued two 1/4 x 1/4 balsa stick spaced by 1.5 inch over the two forward fiberglass tube sleeves inside the fuselage and tie-wrap around the tank "Keep It Simple Stu..." weigh nothing and permanent. The small tank is only 15$ but much too small air reserboir for three gear. You mya cycle them safely once only. The medium tank is what I'm using for the gears. I keep the small forward tank for the bkakes.

normand

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

GUYS I HAVE ONE SMALL TANK FROM ROBART AND TEST IN HOUST AT 70 LBS ( AT THE FIELD 120) I GOT 7 COMPLETE CYCLES ON THE SMALL TANK SO DONT WORRY. THE BIGGEST BIND IS WHEELS TOO BIG OR CROOKED MOUMTS. IF YOU BIND UNSCREW ONE MOUNT SREW AND SEE IF IT HELPS. YOU WILL FIND THE LOW SIDE , ADD ASHIM AND YOUR OK

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

What servos on the rudders did you guys used?

Can I use these one?
http://www.horizonhobby.com/Products...rodID=JSP20030

Thanks!

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

Hello Abras,

This is the servo you whant for the torque needed

http://www.horizonhobby.com/Products...ProdID=JRPS341

Normand

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

the manual tells you what to use follow that!

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

That servo is the equivalent to the futaba. If you use JR it sounds better to be JR all the way!

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

Also you could consider these:
http://www.hitecrcd.com/servos/show?name=HS-85BB

Don't want to get caught lacking in rudder authority on a big twin if you lose an engine.

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

Tim. Just wondering. I see and have ordered a OS 81FS-a from the Tower site. However, when I go to the OS web site I cannot find the OS 81FS-a engine listed. Can you explain this. Thanks, Bill.

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

it is a brand new engine. Probably not on the website yet. Before X-mas Tower did not even have a pic of it. OS 81

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

Just been fitting the nacelle doors - holy cow![X(] Finding that last split washer in a tray of about a gazillion screws, nuts and bolts was bad enough, then adjusting all the ball link sockets to exact length, then adjusting them all shorter, then having to file down the screws which are now impinging on the sockets, then trying to simultaneously hold 8 hinges straight (o.k. - admit doing both nacelles at once..:)) whilst epoxy paste cures........AAAARRRRGGHHH!!!!!!

Next plane will have fixed gear........

So, when gluing the hinges to the doors, temporarily tape the other side of the hinge to the nacelle whilst epoxy cures, that way they don't slowly drift out of alignment. Once cured, gluing second half of hinges to nacelles should be easy by comparison...

Never did like retract doors, does it show? Good luck doing the sequenced doors with "extra" doors electric Tim - I'd need a good sedative first![8D]

Cheers,

Cam

p.s. Anyone have pics of where they put their nosewheel steering servo who has bomb bay?

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

What battery are you going to use? I just ordered a 5200 Mah lipoly pack and a regulator. This will then go through the smartfly power expander. 6 volts to all 13 servos. The voltage will also stay constance now. The guys at Fromco said I sould get 7 flights in one day before I start to see a voltage drop.

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

Hi Bill.

I don't know why the new .81 doesn't show up on the O.S. site. Probably the guy who manages the site just got behind. [sm=71_71.gif]

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

Hi again Bill.

Didn't want you to think I haven't been reading your posts--I was sick yesterday and our computer at home died!

Yes. Keep us updated on your progress and don't hesitate to ask any more questions!

You'll love the sound of twin four-strokes in your B-25!

Thanks!

Tim

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

my doors went on easy in about 30 min. have you ever done scale doors before ,it just takes practice. This design is very well thought out

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

Hi all. Love this build/technical thread. Great information from all that have contributed. I am just building my B25. I ordered two FL70 OS Engines as the Surpass II no longer available. Will these engines work ok and fit right in as per the plans. I believe from the review on the B25 that Model Airplane Magazine had in it these same engines (FL70) were used.

Thanks all who have contributed so far.

Cal.

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

Cam,
Take a look at Tim's pic in post #657...the servo mount will be foreward of the bulkhead at the front of the bomb bay. I removed the existing mount and reused it at the new location. I made a removeable panel in that bulkhead so access was a bit easier.


Doug

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

Hello Cal.

I don't really have much to add here, except to say that I think you'll be just fine with those FL 70s. We never tried the B-25 with the FL 70s as they were not available when the project was in development, but same as you, I have read the review in Model Airplane News (I think it was), plus another review on the B-25 with the FL 70's in another magazine. Both reviews praised the way the B-25 flew with those engines. So, I cannot speak from experience, but based on hearsay (from the magaizine reviews), and based on the way most O.S. engines run, and based on the power rating (1.1 hp compared to 1.1 or was it 1.2 hp of the Surpass II?), your B-25 will fly well.

Should you elect to try out 3-blade props though, please make your first flights with 2-blade props because they usually provide the most thrust. When you get more time on your engines and get used to flying your B-25 you could try 3-blade propellers. I like the Master Airscrew 12 x 8s the best (on the O.S. 70 Surpass), but I wonder if your FL 70s would do better on 12 x 6s? You'll have to experiment.

Be well.

Tim

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

Thanks Tim. Good advise on the props. I will try that.

Cal.

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

Really nice one. I have a used OS 70 Ultimate. Can I by one more and expect that the new one will run the same rpm as the used engine? Think this is a nice choice of model...

Yngve, Norway

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

Oh yea Cal, I forgot to mention, we liked the APC 13 x 6 (2-blade of course) props best on the 70 Surpass IIs. I guess that'd be the place to start on those FLs.

If you go back near the beginning of this thread you'll find more discussion about propelles.

Take care now.

Tim