RC Groups

RC Groups
    Scale Kit/Scratch Built
        Discussion 52 inch span B25 free plans

#1 sparks Sep 18, 2006 09:08 AM

52 inch span B25 free plans
 
6 Attachment(s)
Here is a 52 inch span B-25 that you can build for under $70 bucks easy. .(Airframe only, not counting motors ESC's and radio gear.
If you have never built a model with foam and not afraid of a little sanding this is a good one to start on. The sides are relatively flat keeping the sanding to a minimum. The only place you might stumble is getting a good fit between the wings and nacelles. Even then it's just foam, 120 grit really eats this stuff up.

#2 sparks Sep 18, 2006 09:12 AM

Plans
 
7 Attachment(s)
Ok here is the deal. . . .I have to come clean right off. it's not really free plans it's more like free foam cutting patterns and a three view but that's all you need to build this plane.
It's based on a four inch wide fuselage so you can build it with 2 inch blue foam.
A half sheet 4' X 4' is enough to make one plane. A whole sheet of 2 inch blue foam (4' X 8' ) runs about $26.

developments:
My model took 4 oz. of ballast in the nose just behind the gunner.
with the wing incidence set at zero at the root the stab needs 2.5 to 3 degrees of nose down to fly level. E-flight 480's provide more than enough power to fly the model and only pull 20 amps. this makes a three cell 2100 MAH pack useable.
Notice:
the wing span to my model is from tip to tip 53 inches. The wing cores were cut to the point that the tips start to curve ( top View). This does not correspond to the three views .
In other words I cheated a little. After seeing how the model flies the scale layout will work just fine ( 48 inch tip to tip) so stick to it. My next one will.

#3 sparks Sep 18, 2006 09:20 AM

plastic parts
 
3 Attachment(s)
The plastic? nose greenhouse windows (2 pieces). cockpit windows, upper turret. observers bubble, side gunners windows, tail gunners bubble, two cowls and the entire flight crew. (6 figures) and the guns under the cockpit. $27 shipped in the US.
this is enough parts to build your favorite model with the exception of the G and H model.
You should note that the panel lines are not formed into the windows.
Normally I do put the lines in my tools but about 10% would find fault with the thickness, width and location of them. Besides this will give you model options.
Drop me an E mail and I'll fill you in on shipping and payment options. parkflyerplastics@att.net
You first timers Say the word and I'll throw in the book "building with foam" and you can save the postage.

#4 sparks Sep 18, 2006 09:21 AM

This is going to feel like you walked into a movie a half hour late. Originally I was just going to build this one just for me.
Ron Singer (of the EAM B-17 fame) wanted one too so I cut his while I was doing mine.
Well mine is nearly ready to paint and load up with the flying gear. Ron and the people I fly with has persuaded me to post the model and offer the plastic. Not knowing how well it will fly, I have reluctantly agreed.
My version. . . .
Without the landing gear and radio equipment my model weighs in at 1.5 pound. I'd bet it would fly with a pair of E-flight 450 outrunners but to be safe I'm going with the 480's. The wings are not removable and are covered with one ply of 3/4 oz cloth because I used white beaded foam for the wings. a single sheet of 1/8 light ply connects the wings at the fuselage centerline. the rest of the model has been covered with two ply of .5 oz cloth. I have elected to install functional rudders, ailerons and elevators and flaps just for fun. No retracts, no bomb bay. .
Every time you add a feature the weight goes up . . .Duh.
If I made the model with no glass cloth, landing gear, rudders, or flaps I'd bet it would weigh half at this point.

Ron has elected to sheet his wing, this allows him to skip weight of a spar. This decision was made because he intends to make his wing removable for transport. The down side is he looses space in the fuselage. Ill post his progress as well.
Right now we are facing tail heavy models but time will tell how heavy.

#5 sparks Sep 18, 2006 09:31 AM

Ron's plane
 
6 Attachment(s)
To cut out the parts for the B-25 you will need a hot wire and patterns / templates.
Construction for both are in the book. The tail feathers have been cut from the 2 inch blue foam at just under 1/2 inch thickness and then cut out. Below you can see that Ron is using balsa as to dress the hinge lines. This adds stiffness and allows ca to be used to attach the hinges.

#6 sparks Sep 18, 2006 09:46 AM

Gun ship
 
6 Attachment(s)
Ron is going to do the gun ship version so he is not going to use the forward windows.
Not a bad choice. This will hide the battery all the way up front helping the CG sanitation.
Entry for cell replacement will be through a hatch cut around the cockpit plastic. Note the balsa edge to support the hatch.

#7 sparks Sep 18, 2006 10:03 AM

Nacelles
 
3 Attachment(s)
Ah, the nacelles, bit of a pain but it has to be done.
Start with two blocks of 2 inch foam.
Bond them together with two drops of epoxy applied to the centerline front and back.
Use the template to cut it into a cylinder.
All that's left is to cut the top and side profile and the wire cutting is done.
I have no cutting illustrations to show but it's done like I did the nose to my 757 so I used those photos.. . .Sorry :o
Put the hot wire away and get out the 90 grit sand paper and start shaping.
This goes fast so when you get close go to 120 grit and finish with 180.
Don't forget to mark the top and bottom.
The photo below shows where Ron has to hollow the rest of the nacelle out with a rotary tool.

#8 sparks Sep 18, 2006 10:10 AM

Motor mounting
 
2 Attachment(s)
This one is my model. I came up short on the nacelles so I had to make a motor mount block.
A light ply plate is bonded to the nacelle and glass has been folded over to it's edge for additional support. I prefer to use magnets to hold my cowls on.
No screws to mess with and 1/8 inch twist removes it from the model.
The light ply ring inside the cowl makes it rather strong too. I plan to have the air flow through the nacelle and out through the gear door.
Run the wires before the face plate is installed.

#9 ron s Sep 21, 2006 05:55 PM

:D thanks sparky for posting this build! had a good build day today took more pics hpoe to get them to you soon for posting.

#10 portablevcb Sep 21, 2006 06:17 PM

Very cool Sparky. Now I know what you've been doing in your spare time :D

charlie

#11 Synwpn Sep 21, 2006 10:23 PM

Thanks for the templates Keith! I think I'll have to try this one! :D

#12 sparks Sep 22, 2006 03:40 PM

Painted
 
8 Attachment(s)
Well My plane is all painted and ready to put the flying equipment in.
Ron's plane is getting the wing saddle installed as well as the battery hatch.
You can see the grooves he cut in the stabilizer to install the rudder cable tubes.

#13 sparks Sep 22, 2006 03:42 PM

Painted
 
2 Attachment(s)
Forgot my model. . . . :o

#14 newcomer Sep 22, 2006 04:28 PM

Sparks. bought the book - love it.
what are you using to mask the canopy?
david

#15 ron s Sep 22, 2006 05:40 PM

newcomer, im using blue seethrough mylar tape to mask the windows.


All times are GMT -5. The time now is 06:28 AM.