William Robison

My Feedback: (3)

Sam:

I see the rear panel of the tail gunner's greenhouse you mentioned being painted. Yes, it's supposed to be clear.

Bill.

rcmiket

Nice work, I saw one one of these @ the LHS yesterday got to say looked pretty nice. On your engine set up looks tight, are you sure you have enough exit for proper cooling? I'm waiting for some flight tests before I jump into this one. Keep us posted and thanks for the info and pictures.-Mike

samparfitt

My Feedback: (43)

Mike,
I'll be cutting the excess wood off the cowl mount so there's lots of air flowing out there.

Note on the VQ struts:
The 1/2" and 7/16" will need modifications to the internal spring stop to use them.
The 3/8" ones would be much easier to install.

note on the KMP struts:
The nose retract in the kit was not working.
The air cylinder just screws off to get to the 'guts' of the retract.
I found that the 'O' ring on the plunger was broke and the plunger came loose from the threaded rod.
I should be able to get the 'O' ring at the hardware store and the plunger easily screwed back on to the rod.

Air tank:

First picture:
The Robart large tank will fit up front on the fuse.
The 'working end' must be put in first to get it to fit (want it pointing backwards anyway).
If you plan on cutting out the cockpit area then you can use two small one's.

Second picture:
Some velcro on the side and end and she's all set.

Stab (continued)

Third picture:
I put the control horns on at a slight angle towards the fuse to prevent binding of the control rods.
I also put them on first to know where to make cuts into the side of the fuse for the control rods.
A cut off disk in a Dremel made quick work of the slits for the control rods.
Some files were used to cleaned up the edges.
The slits are just about in the center of that one panel on the fuse.

Fourth picture:
The wood dowel and 3 rods plus heat shrink tubing are all included in the kit.
I pre-bent the wires before putting the control rods into the fuse.

samparfitt

My Feedback: (43)

Stab (continued)

First picture:
All hooked up.

Second picture:
End view.

Third picture:
The 'guts' of the fuse.
The elevator servo is on the right in the picture.
The servo control arm is exactly in the center of the fuse to insure equal movement to each elevator.
The air valve was also mounted and the servo connected to it.
The kit has the air valve, wood base and screws to hold the valve to the base.
The air valve is a good place to use one of your old servos (functional but not a lot of torque).
I had to drill and tap the plastic connector that goes on the end of the control valve rod.
I used needle nose pliers only on the tapered part of the valve rod to hold it
while screwing the plastic connector to it, so not to scratch the main rod's surface that routes the air.
The battery pack is foam covered and in the lower left of the picture.

Fourth picture:
The top of the wing where all wires come out that go to the fuse.

CB1000C

My Feedback: (6)

Samuel,
First of all excellent job on the documentation of the B-25 assembly. I also have a KMP B-25 kit and have been eagerly reading your posts on a daily basis. I thought I'd try and assist you with your retract issue. My nose gear retract O-Ring was also split on my kit. When I tested the retracts it was obvious that something was wrong with the nose gear retract from the amount of air leaking out of the plunger assembly. I was able to find a replacement O-Ring at my local Ace Hardware store. They are Metric O-rings and the size is 2mm width by 6mm I.D. I had to go to several places before I found someone that carried Metric sizes. Beware of the O-rings that are listed as both Standard and Metric size. they are not true metric size and will not work. they are either a tad big or small. Keep up the good work.

P.S When do you expect to maiden it?

Bret Webster

TLH101

My Feedback: (90)

Well since Sam showed the engine set-up with 2-strokes, I will add a few pics of a 4-stroke set-up. I mounted mine on the side, but I thing you could go inverted or at a 45 degree down angle.
One thing I almost missed in the instructions, was the fact that the motor C/L needs to be raised above nacelle C/L by 4mm. Apparently there is a little down thrust in the firewall. It is clearly shown in the manual, & I saw it before I drilled any holes.

TLH101

My Feedback: (90)

BTW, with a four stroke, I think there will be plenty of cooling as the head is a little farther out of the cowl, and there is a lot of room by the cowl mount ring. I did remove the section of cowl ring directly behind the cylinder to help with cowl removal though.
I think I am going to put some Sand camoflage on mine, paint the bottom of the wing $ stab in lt grey as well.

samparfitt

My Feedback: (43)

Terry,
I didn't noticed the down thrust: must of been why I had to drill 4 more holes about
1/4" higher to get the engine shaft to be centered in the cowl!!!
I see you glued your wood mount to the cowl per the manual.
I'm not sure which way I'm going yet: that way or the 'traditional' way.
(just looked at picture 11 in the manuel: completely missed that)

ps: the prototype seems to be painted OD and our's seem to be a few shades lighter!

pps: I found 2 pieces of short metal rod in the kit: I guess they give you the option of using
these or the one larger piece for the pins in picture 48 for holding the stab to the fuse.

TLH101

My Feedback: (90)

I thought that some others might miss it, so I pointed it out. I just got lucky. It's on page 3 step 11, for those who are not there yet. Gotta love that manual, but I guess that most people building this plane have done a few before they get here.
That's the point of this thread anyways.

samparfitt

My Feedback: (43)

Struts.
These are the VQ 1/2" diameter straight struts.
At a 1/2", these are very sturdy.
These struts are made for a larger plane
so considerable modifications are needed to make them fit.
Use the 3/8" ones if you want to eliminate all this work.

First picture:
To get these struts to mirror the kit's wire ones for the same length,
I had to cut 1 1/2" off the top of the strut.
I used a large cut off disk to do this.
In the picture,
the strut that we are going to use is on the left
next to the right is the part of the strut that we just cut off,
next are the 2 black plastic plugs that the oleo spring pushes against,
these were exactly below where I cut and I used a rod to knock them out.
We won't be using these again.
Next in the picture are the metal plugs we will be using to 1) put the wire in to hold the strut to the retract
and 2) be used for pressure on the oleo spring.
To the far right is the 5/32" rod we'll use to connect the strut to the retract.
This wire is the same size as the kit's wire strut.
The metal plugs that come with the VQ struts are only for 1/4" rod.
I don't know if Mike at VQ has a 1/2" plug with a 5/32" hole.
You could drill out the retract for the 1/4" rod but I thought this would weaken the retract.
Instead, I used two pieces of brass tubing to 'step down' the 1/4" plug hole to the 5/32" rod.
I had to use two pieces of brass tubing for this (shown in the bottom of the picture).
I'm not sure on what sizes they are but I had them lying around the shop.
Any good HS will have tubing and you can just 'check and fit' until you find the correct sizes.
(hey, I told you this is a lot of work!).

Second picture:
Here's the 'step down' pieces of brass from the metal plug to the rod.
Some J/B weld can be used to hold it all together but mine had enough friction between them to stay together.

Third picture:
The two pieces of brass should slide in by hand into the plug.
Use a vise to press the plug into the strut.
Make sure you put wood on each end to protect the ends of the strut.
If you damage the oleo end, it's not going to slide very well.
You could use a persuader (hammer) but a vise is easier to use and less likely to damage the strut.

Fourth picture:
Ends of struts showing the plug and 2 brass tubes.

samparfitt

My Feedback: (43)

Struts (continued)

First picture:
We need to drill and tap the struts for the set screws.
You have to do this no matter what strut you buy unless the strut is part of the retract.
We need two set screws (nothing worse than only one screw!).
I put the two set screws at 180 degrees but 90 or any other is fine.
First we need to use a small diameter drill bit to drill a pilot hole.

Second picture:
Next we use the proper size bit for the tap.
Make sure you use cutting oil for drilling and taping.

Third picture:
Tap the hole.
I used the cutoff piece of strut for a sample to insure all works OK before doing the main strut.

Fourth picture:
Set screws and wire are in.
Make sure you file in those flat spots for the set screws!
The rod will only stick out about an inch from the strut.
That's all the rod needed to go into the retract.

samparfitt

My Feedback: (43)

Struts (continued)

First picture:
Since we put the plug where the existing black plastic plug was,
we don't need to cut the spring shorter but I thought the oleos were too stiff for this size plane,
so I cut some off.
The bottom spring is 2 pieces that I cut off.
I first cut off 3/4" but the oleo was still too stiff so I cut off another 1/4" and that seemed pretty good.
The top spring is where I just cut off an inch off the second spring.
Hard parts done.
Now assemble and put her on the plane.

Second picture:
Using 4" Robarts will require some trim on the nacelle.
There is a faint pencil mark where I need to trim.
This is a reinforcement area so it won't show when the fiberglass cover is put on.

Third picture:
Those big tires makes her pretty close to scale size.
Cool.

dajensen

Another source for struts is robart, I plan on using the robart Wing Mfg retract set P\N WB25 Tri-gear set for $385. The set consists of 100 degree nose gear unit with a 3/8 inch right offset strut and the mains are a special length 1/2 inch strait strut. The strut is clamped in the retract trunion instead of being set screwed to the LG wire. Also don't know if anyone is into scaling their bird like I am, but Glennis Mfg makes a scale set of wheels and brakes for the Wing Mfg B-25 for $375, which BTW is the same scale and almost identical in size. If interested give them a look at this link. http://www.glennis.com/bombergallery.htm BTW Sam, with the rudders being on 2 different servo arm holes what is the difference in deflection between the two rudders?

samparfitt

My Feedback: (43)

The rudder deflection difference is noticeable but since they are both doing the same thing (either right or left),
I figured it makes no difference if one moves more than the other.
Kind of like the ailerons, if one goes up a little more than the other one goes down, no big deal.
Not the same for flaps or elevators: that's why I modified the tube routing on the flaps.
If you have a problem with this, you could always use just one wire from one rudder to the other and going
through one easy link: now I think of this: this would have been a lot easier than the kit's method!!

I haven't check but the kit's retracts should be checked to see what degree rotation is done.
Since the mount is tilted, they may only be going about 75-80 degrees,
so if you get new retracts, they may be hitting the top of the nacelle or not retract completely.
Of course, you can just shim up the mount to make it horizontal.

samparfitt

My Feedback: (43)

Struts (continued).

First picture:
On the left is the 7/16" strut and the right is the kit's nose strut.
Allowing for attaching the wire to the retract plus the steering arm,
the kit's strut wire would meet the bottom of the steering a 1/4" above the coil in the wire.
Transferring this length over to the oleo strut leaves very little strut left for the oleo and spring (lower light pencil line showing
on the oleo strut where I would have to cut it).
There's another pencil line above that (about 1 1/2" up) that shows where the plug that holds the spring is located.
Cutting for the correct length would just about eliminate the spring
and may even require some cutting on the lower male end of the strut.
For now I'm using a 3/8" diameter oleo strut.

Second picture:
I had a spare 3/8" diameter strut for the nose.
Following the same procedure as with the mains,
I cut the strut to length, knock out the spring plug, put a new steel plug in,
drill it out for the wire that connects the strut to the retract and drilled/tapped the strut.
The manual shows the steering arm with the sleeve of the steering arm farthest from the retract.
(picture 38 shows it incorrect, the last page (back) shows it correct).
This has to be reversed as it prevents the retract from going up.

Third picture:
The wheel size is pretty scale.
I just hope it's strong enough for this plane.
Most of the weight is on the mains so this may work.
There's a big difference between the 3/8" and 7/16" strut for the holding the 'scissors' on:
One is thin sheet metal and the other is a thick cylinder.
The thin sheet metal bends easily if enough side force is applied (as in turning at too high of a speed or too quickly):
The plane then has a lot of play in the nose and is hard to steer making it hard to take off.
If this doesn't work I'll just have to butcher up the 7/16" but there will virtually be no oleo affect due
to having to cut the strut so short.
This kit's strut length only allows about a 1/4" room to fit in the fuse.
The retract mechanism could be moved forward about an 1" by cutting some ply out,
but then the mains would also have to be lengthened.
The present strut length seems about scale since the B-25 appears to 'hunker' down low.

Hmmm, I might be able to strenthen that thin metal by putting a piece of tubing on the pin and JB welding it to the strut.

dajensen

Just an FYI for those doing a full scale out on this bird. The mains have a 5 degree forward rake and the nose has a 12 degree forward rake. Also the main oleo scissor is pointing forward NOT rearward as one would explect. I think, but need to confirm, that this would require a 100-110 degree main retract in order to get the mains to fully retract into the nacelle. I will check the angle of the mount and make sure and post the actual swing required. Just my 2 bits worth for scale

samparfitt

My Feedback: (43)

It appears that the 'scissors' faces backwards in the pictures I've seen.
I may reverse this because it hits the retract air tank when it is in the up position.
Function over looks and most people don't know or (at some of our ages!) don't remember those details
since this was not a standard for all planes to be either always forward or always backward.
I don't have all the 'stuff' on the plane yet but so far, it appears that the mains are just behind the CG.
If the mains are suppose to rake forward then the kit has them backwards.
Maybe the importer did this so the plane doesn't fall on it's tail.
If this is true, raking the mains forward will definitely present a problem.

dajensen

Sam,

I sure hope that it is just a case of the manufacture doing some things wrong and not because they had too. Like the way they did the mains with the wheels facing in instead of out. It just seems like it would have been just as easy to do it correctly as the formers look symetrical and ,if that is the case, they could have swaped the left and right nacelle formers to have the gear face outward with no mods by the builder. But that is just me nit picking a great looking ARF. It is my hope to be able to make new LG fairings so that I can incorporate gear doors into them. It would sure throw a wrench in the works if the gear has to be raked back like they have it. I may just have to make completely new mounts and move them back, not that this is a problem, just a pain. BTW I am quoting the gear specs from the Squadron signals publication The B-25 in detail. Excellent publication for detail buffs or folks that just want to know more about this bird and it's history.

mtrounds

My Feedback: (1)

Sam:

You are a big help to all that have the B-25! I am all most do on my F2G. Then I will starting on my B-25. So I can work out all that is needed to do the elect. power. Keep up the GREAT job!

_____________
Mike

samparfitt

My Feedback: (43)

Well, I hooked up the air system to the retracts.
I followed the schematic on the last page.
The kit's 'quick connect' (the black cylinder with green ends) leaks badly.
I put a Robart's quick connects in place of it.
The tank still didn't fill up: The air routes through the valve into the tank
so I moved the valve back and forth and still the tank did not fill up.
I then put a Robart valve on and the tank filled up.
The retracts go up very fast but down very slowly saying that the springs in the retract air cylinders are on
the weak side.
In the down position, the mains have about a 1/2" wiggle forward and backward as does the nose.
Unless that wiggle can be removed somehow, I'm going to have to replace them.
Another 300 bucks I wasn't planning on spending.
Now that I've cut my struts to hold a wire, they will be too short using the spring air ones since
the strut connects directly to the retract made by Spring air.
Very discouraging: think I'll go watch some March madness.

TLH101

My Feedback: (90)

Sam,
I feel your pain.[:@] At least you have remained calm & didn't throw a rant like I did earlier.
I am going to use a set if Spring Air retracts that are set-up for the 3/8 strut. The set I have are not exactly what is needed. They are 500 series that retract outboard, so I have had to make some minor changes in the mounts and throttle servo linkage.
VQ has a set of S/A 102HD for the P-38, that are bored for the struts, and they look like they would work perfect. Or you could order a set of 102HD's from S/A that are set up for the wire & used the struts you already have. You might also look at the Robart 530RS & 557RS. They would be pretty close to scale: http://www.robart.com/retracts/8-18lb550.aspx
Hang in there.

samparfitt

My Feedback: (43)

Terry,
thanks for the info.
Interesting on how those retract go in the opposite direction.
Seems like those will work just as well.
I was considering the same kind as I got for the P-61.

Decals.
Well, while watching march madness, I did something that I figured would work.
After 'hot gunning' all the fabric to remove any (plus future) bubbles, I put the decals on.
These decals are real nice: a mat finish so they blend real good with the paint.

First picture:
The left side with the Captain's (pilot) name under the cockpit.

Second picture:
The right side with co-pilot and 42 bomber emblem.

Third picture:
shield and plane number.

Any body know where 'ed watchdog' goes.
It looks like the right front but not sure.

warks62

My Feedback: (140)

Thanks Sam for all the help so far. I guess the Corsair is on the back burner now? Picked up my B-25 up tonight getting the boxes open now. Should be fun.

samparfitt

My Feedback: (43)

yep, I still gotta' finish up the doors and few more things on the GSP Corsair, about another 6 hrs of minor stuff on the P-61
and finish up the TF GS ARF P-51.
Made some 'relocations' of the air tank so I could put in a 40 oz tank for the Revolution 52 in the P-51 which, when I get back to, will post on a new thread. That engine with the scale exhaust is one cool combo.

warks62

My Feedback: (140)

Well started mine this morning one thing I am going to do is use 2 Elevator servos up front. Going to add another dowl and servo. Would rather have a little redundacy. I have always liked the idea of 2 Elevator and Aileron servos just in case one acts up. Kit looks good not perfect but good for the price. I think it is a great deal all in all. Going to have to pick up some cables for the Rudder and Flaps. Bummer that it doesn't come with them. Just don't see the need for 4 Flap servos. May look into 2 Flap servos but haven't started the wings yet working on the body right now. Thanks again Sam great thread.