FMS B-25 Crash Questions and Comments . . . .

[Skywagon]

The other day I lost the FMS B-25 in routine flight. It suddenly rolled over and went in hard.
All the usual suspects were essentially put aside as it had a good pre-check.
This model is famous for its cable "nest" that you have to figure how to neatly store in a very limited space. And, this takes most of the space. Then you have to find place to mount the receiver. Everything is "packed" into this small hold.
I am thinking that the model got into an orientation to where the cable cluster either blocked the Tx signal or reduced the received signal so low that any rf noise in all the cabling and motor wires over whelmed the receiver long enough to have it loose control.
When I build the next B-25, I believe the receiver should be located as far away from this nest of cabling so it cannot be a cause of interference.
I am not familiar with where one can cut out a compartment in the fuselage to house the receiver and not affect the structure strength.
Any suggestions would be appreciated from the forum guys , , , ,

[Alpha]

Hi Skywagon, welcome to Hobby Squawk! The FMS 1400mm B-25 is one of my favorite multi-engine foamies to fly, but you're right that the rat nest of wires can become potentially problematic. I sliced a cavity under the wing about an inch behind the CG point to mount my receiver. There's a foam floor in there. I don't have a picture, unfortunately. But don't worry too much about compromising structural strength as long as you only cut a small hatch and not a huge one that goes through bulkheads and floors altogether. Relocating the receiver to this location and organizing the wires with small zipties greatly freed up the space in the front. I flew with an Admiral 3s 3700.

Best of luck to you with it!

[TiredIronGRB]

What about putting it where the bomb bay would be? Oh, and welcome to Hobby Squawk!

[borntoolate]

Hi Skywagon, Welcome to Hobby Squawk. The FMS 1470mm B-25 is certainly one of my favorite planes... or should I say 4 of my favorite planes! I have 4 currently operational and I really love these.

The wiring can be a mess. It looks like a rat's nest. I solved my wiring/space problem by creating a receiver bay behind the cockpit. It allows you to mount your receiver in a convenient place. All the wiring will go into the tunnel behind the cockpit. All 4 of my B-25s are modded this way. The mod is actually pretty simple. There is a 4" hatch on the top of the fuselage that uses rare earth magnets to hold it in place. I use a separate RX battery with a CC10 amp BEC. The tunnel has room for this extra battery as well as the wiring that previously looked like spaghetti.

Here are a couple of pictures that shows the mod. You can visit my blog to review how to do this as well as some other neat mods for the B-25. The blog is located here:

https://www.rcgroups.com/forums/member.php?u=407814&page=2

There are mods for other planes as well as the B-25. If you have any questions, I would be happy to answer them for you.


Bob

[borntoolate]

Oops! I forgot to add the pic with the receiver hatch in place.

Bob

[borntoolate]

By the way, no bulkheads or floors were harmed in this modification!

[Alpha]

That's a really nice color scheme, Borntoolate!! Full picture, please?

[Skywagon]

Thanks for the suggestions and photos of B-25.

I like the suggestion to cut a small hatch in the belly about where some have installed a bomb bay option and install the Rx there as one pic shows.
However, there are times when you might want to get to the receiver; about how to make the hatch removeable; e.g. re-binding, etc. Also, I would like to always confirm that the Rx is fully linked to the Tx and I to "see"the LED on the Rx to verify this. If it is in a belly hatch, you can't easily review the Rx LED status.

With the hatch access suggestion, maybe all the excess wiring could be easily dragged back in that cavity towards the tail, leaving the forward bay nearly free of all wiring other that the Lipo connection. That way, with the normal pilot hatch open, one could mount the Rx in such a way that the LED could be observed and the Rx would basically removed from the wire cluster mess problem.
Keep the ideas coming. This bird is not cheap when it gets "re-kited" with a hand full of dirt.
P.S. I too use the Admiral 3700mah size Lipo. With a little foam removed it fits well and helps with the CG

[Skywagon]

Hi Skywagon, Welcome to Hobby Squawk. The FMS 1470mm B-25 is certainly one of my favorite planes... or should I say 4 of my favorite planes! I have 4 currently operational and I really love these.

The wiring can be a mess. It looks like a rat's nest. I solved my wiring/space problem by creating a receiver bay behind the cockpit. It allows you to mount your receiver in a convenient place. All the wiring will go into the tunnel behind the cockpit. All 4 of my B-25s are modded this way. The mod is actually pretty simple. There is a 4" hatch on the top of the fuselage that uses rare earth magnets to hold it in place. I use a separate RX battery with a CC10 amp BEC. The tunnel has room for this extra battery as well as the wiring that previously looked like spaghetti.

Here are a couple of pictures that shows the mod. You can visit my blog to review how to do this as well as some other neat mods for the B-25. The blog is located here:

https://www.rcgroups.com/forums/memb...814&page=2

There are mods for other planes as well as the B-25. If you have any questions, I would be happy to answer them for you.


Bob

Bob, How do you keep the top hatch attached. ?? I am assuming that you do no glue it down as one needs access from time to time.

[borntoolate]

The other picture does not show it, but I have 4 small rare earth magnets holding it down. It is very, secure. Here is a closer look.

[rifleman_btx]

Lemon Rx! I love these receivers!

[borntoolate]

That's a really nice color scheme, Borntoolate!! Full picture, please?

Thank you Alpha. Here is a pic of her maiden. This one I modified from a B-25J to a B-25B. Modeled after the Ruptured Duck, plane #7, piloted by Lt. Lawson, on the Doolittle Raid.

Sadly I lost her to a LOS about 8 months later. I recently replaced her.

Bob

[borntoolate]

Thanks for the suggestions and photos of B-25.

I like the suggestion to cut a small hatch in the belly about where some have installed a bomb bay option and install the Rx there as one pic shows.
However, there are times when you might want to get to the receiver; about how to make the hatch removeable; e.g. re-binding, etc. Also, I would like to always confirm that the Rx is fully linked to the Tx and I to "see"the LED on the Rx to verify this. If it is in a belly hatch, you can't easily review the Rx LED status.

With the hatch access suggestion, maybe all the excess wiring could be easily dragged back in that cavity towards the tail, leaving the forward bay nearly free of all wiring other that the Lipo connection. That way, with the normal pilot hatch open, one could mount the Rx in such a way that the LED could be observed and the Rx would basically removed from the wire cluster mess problem.
Keep the ideas coming. This bird is not cheap when it gets "re-kited" with a hand full of dirt.
P.S. I too use the Admiral 3700mah size Lipo. With a little foam removed it fits well and helps with the CG

The reason for the receiver hatch on top was partly for convenience, accessibility and because I had added a working bomb bay.


Bob

[borntoolate]

Here is a picture of the 4 operational B-25s I currently fly. The picture includes the replacement aircraft for the Ruptured Duck, which I lost to LOS a while back.

Bob

[TiredIronGRB]

Bob is out of control on bombers, I just don't understand it :)

[Prowler901]

Nice PBJ there, Bob. And the Ruptured Duck has been my favorite since I saw 30 Seconds Over Tokyo as a kid. Great movie.

[borntoolate]

Bob is out of control on bombers, I just don't understand it :)

Hahaha, said the pot to the kettle!!!

[borntoolate]

Nice PBJ there, Bob. And the Ruptured Duck has been my favorite since I saw 30 Seconds Over Tokyo as a kid. Great movie.

Thanks Prowler901! Thirty Seconds Over Tokyo is my absolute favorite was movie.


Bob

[rifleman_btx]

Might have to set one of these up for FPV with a down angle camera that acts like a bomb sight. That would be so fun

[dkalwishky]

Oh great, now I NEED an FMS B-25. We've got a club member here who has one and he loves it.