samparfitt

My Feedback: (43)

Pilots,

While at Toledo, Bruce at CJM took my order to make some new bomber pilots for the 118" B-25.
I just got them in the mail and they look great.
They appear to be made out of some kind of a cast resin.
(Sorry about the pictures: I should have taken the pictures, outdoors for better lighting)

Mustangman40

My Feedback: (1)

Subscribed Sam, looking forward to your build.. This plane is in my near future, so I will follow yours with much intrest...

Jimbo

alanc

Do you have a link for the CJM pilots? mate of mine just cannot find any the right size, same model the 118" B25, could do with some reasonably priced cockpit detail sets too, if anyone has any leads

samparfitt

My Feedback: (43)

1. Since the bomber pilots are new for the 118" B-25, you may have to contact Bruce at CJM:

http://www.centuryjet.com/


2. only cockpits for a Ziroli B-25, that I know of, are from Dbalsa:

They have just the cockpit for $100.
http://www.dbalsa.com/accessories/cockpits.htm#SS

alanc

Thanks, i have fired off emails to them both, airplane at the moment is flying in grey primer with the cockpits taped on, it has to go through 6 test flights before it can be show flown,when its done its certification flights, it will get finished, its performed superbly so far, the only alteration the guys have done is to remove SWAGES of lead out of the nose, now, it can be brought in on half flap, holding the nosewheel high in the air,flys like a trainer, but has SO much presence, i will see if i can drop a vid link on here, its test flights where off the runway at the old, now sold, BAE Woodford factory runway, the birthplace of many many historic aircraft, Lancaster, Vulcan, Nimrod (less we say about that one the better!!!)

alanc

http://www.youtube.com/watch?v=04OnZ...ature=youtu.be

found it, this is just a short video of Alan flying his B25, Dave, the big guy stood there, is the chairman of the lerge model association, and has a vast amount of experiance with large twins, he has done the test flying of the model, Alan has been flying it on a buddy box link, this is his first flight without the dual control link, he did ok, he is just not expeieanced with this type, or size of model, got to start somewhere!!! this is Woodford, its all ours every ssaturday and sunday, notice in the distance, Vulcan xm603, this is the resident vulcan

bentwings

We are getting very close to flying the B-25. My son took time out to build an Ultra Sport 1000.?? He has a couple of OS 1.08's that he wanted to try out. Additionally he wanted some practice with a big airplane.

My did some more work with the gear adjusting the springs and shims. I think they will be ok but those heavy Glinnis wheels are a concern on landing. I'm sure there is a huge torque loading when they touch down on the pavement if you land very fast. I think the 5/16 axels are going to be a necessity. I have looked at stronger knee links but I moved to another shop site and we don't have machining facilities yet.

I just finished the scale exhaust. It is not "exact" but it looks like 'scale' and is functional with the openings close to the scale location. No mufflers.....warbirds don't have mufflers. haha I have a few pictures that I need to dig out of my camera. They are constructed from copper tubing and TIG welded with the flanges silicone-bronzed welded to a copper flange adaptor.

I'll get pictures out shortly.

alanc

Alans has the glennis wheels, but he has fitted the twin ram robarts designed for this model, BUT, one side, curiously, had a weak spring, the model noticably leaned down on one side,he got 2 more springs from robart, we still where wary of them, so i turned up some brass spacers, to give them more power, now, all is well, 2x108s, is yours the smaller version of this model?

bentwings

Our B-25 is the 118-120" advertized or actual. haha

alanc

then 2x 108s will be nice for taxyng it around, but for flight? Hmm Alans at the momnt is 50lbs, its quite comfortable on 2 xzenoah 38s, but i would not like it on any less, nor, does it want any more its quite perfect, may change when its got detail and paint though

bentwings

The 1.08 are for a sport plane Ultra Sport 1000 not the bomber. G-45 in the bomber.

alanc

AH, my bad, sorry,if you watch Alans in the link vid i put on, you will see it is no slouch, it fair gets along, but it yet has to have details, cockpit, and paint, its expected to get over 50lb

samparfitt

My Feedback: (43)

Prepping:

I've been 'playing' around with my other two hobbies but I think that I'm ready to start to do some plane building.
I was going to first start building the C-45 but I decided to first start with the B-25.
My build tables are hollow core doors so I set set them up in the basement.
Last year, I enlarged the length of the door for the Bates B-26 wing but now, it's still a few feet short for the B-25 wing to have all three pieces of the wing as one. I'll expand the table, later, if I need to.
Fortunately, the other 18" wide door (with extension) is long enough for the fuse.
I've got all the important parts:
Full precision kit cutters kit:
Each group of related parts are bagged or rubber banded together which makes the build go along easier. Major structural parts (ie, wing saddles, spars, landing gear ribs, etc) will be re-cut using aircraft 5-ply to replace the 3-ply wood.
Gear:
Robart B-25 gear. The mains have double cylinders.
Wheels:
Darrell has real nice 6" B-25 wheels with brakes.
Ziroli plans:
The plans are blown up 101" B-25 plans so some 'adjustments' will probably have to be made.
I also got the canopies and FG cowls.
Engines:
Two DA-50's.
Functioning doors, full cockpits with pilots, functioning top turret, functioning bomb bay doors and bombs so the it won't hurt to have too much power (if that's possible!).
I've got 'wrap around' and side mufflers; later, I'll decide which fit better in the cowl.
Cements:
Carpenters glue will be the glue of choice for the bulk of the plane but epoxy will be used on critical stress areas: ie, gear, engine, center wing.
Servos:
Hitec HS-645's will be the 'standard' servo of choice. I'm partial to short linkages so elevator/rudders will have servos mounted in the stab/vertical fin area. One for each rudder and two for the elevator: one on each end (as I did with the P-61).
Each of the four flaps will also get their own servo (another area that I'm 'anal' about versus 'connecting' rods).
Cockpit:
Dynamic balsa kits are being used for the cockpits and century jet pilots will be used.
Covering:
The usual FG cloth with finishing resin and 2-part epoxy primer.
We'll have the panel lines and rivets making the plane 'come alive' and give it a 'soul'.
I've committed to finish any plane that I make that flew in natural aluminum to be covered in aluminum so home depot aluminum duct tape will be used for the finish.
Structural changes:
Since the center wing will be made removable and the bomb bay doors will be functional, as with the B-26, long pieces of 1/8" aircraft ply will be added from the nose of the fuse to the second former behind the TE of the wing to re-enforce this weak area of the fuse.
Fire walls will be extended an inch forward: a dimension that won't be visibly noticed but helps with the CG.
These are my initial building plans and, I'm sure, as I build this plane, there will additional changes made.

ROGER RUSSELL

My Feedback: (12)

Sam:
I know this is a long way off for this question, but please explane or post picture of the above quote!

samparfitt

My Feedback: (43)

Roger,
see post # 213 on B-26 thread:
http://www.rcuniverse.com/forum/m_10..._9/key_/tm.htm

I'm surprised you even asked that question since two threads, the Robart Ziroli P-47 and Bates B-26, already have "how to's", plus you've seen, at least, the P-47! You must be getting old!

ROGER RUSSELL

My Feedback: (12)

Sam:
I thought it was post 211..........LOL

DUCT TAPE is what is throwing me off.........not really called DUCT TAPE, or what I am use to seeing as DUCT TAPE!

ram3500-RCU

My Feedback: (221)

Good project Sam. Looking forward to it.

BTW, the aluminum tape is used for the same thing the fabric tape known as "duct tape" is, sealing duct joints. I use the aluminum tape exclusively for this as it has batter adhesive and is permanent IMO.

I do not prefer this material for covering airplanes as it is thicker, heavier, and only is about 2" wide. Other aluminum self-adhesive products can be bought in 4" to 12" wide rolls, and are much thinner and lighter. "HVAC" tape is however, readily available at hardware stores, and is relatively inexpensive. Having said that, Sam is an experienced and very skilled builder and we all have preferences in building technique and materials. I am in no way second guessing his choices.

Olsen

Hello Sam

I am in the final stage of completing the same model, actually also with a kit from PCK, it goes together very easy, I have only removable outer wings and tailsection so it can stand on the gear.
I have the Robarts too,with Tuff Threads wheels from Robart. I have chosen the RCGF 50 cc flat twin as powerplant 2 Biela 20x10 carbon scale props, canister mufflers from Toni Clark in Germany, they are completely hidden in the nacelle below the tankfloor which I have raised about half an inch. I have a buddie in our local club who have this engine and it has been running very well for more than two years now so I hope it is a good choice.
As you I have covered mine with alu foil it is somthing called Metalcoat from Mick Reeves in the UK it can be bought in whatever length you want and 60 cm.(about 24 inch) wide, very very sticky but I think it looks nice. I have decided to make mine as "Panchito" owned by Larry Kelley on the photos it is only the outerwings that actually are polished. The covering is FG cloth with finishing resin and more than 300 pieces of alu-foil and me and my wife have made more than 18000 rivets using a Top-Flite template and a ball-pen to print the rivets into the surface.

Here is a link to my photos from the build [link]https://plus.google.com/111994526239439977373/videos#photos/111994526239439977373/albums/5783653984996956065[/link]

Hope you enjoy your build and I will be looking forward to follow your thread here, mine is due to fly next spring so I have the winter to finish it of with Gun Pods, Dummy Engines, Turrets, and radio gear.

alanc

GUYS, i have to reportthat the B25 in the video above, has bitten the dust, pilot error, he knows what he did wrong, basically, he was on take off, gear was up, take off flap was down, model veered to left with the wind, he hauled it over to the right too hard, model flicked into the ground, damned shame, it was just getting sorted, BUT, Alan is no quitter, another laser cut kit has been bought, and Jonesey, our builder, is going to do it all over again, Jonesey is at the moment, well on with a Ziroli DC3, its expected though that the B25 will be glassed, and ready for gear install around springtime,engines suffered too, cranks being bent and displaced, i have sorted one ofthem, the other is being looked at next week,

about moving the engines forward, we balanced this model slightly nose heavy for test flights, ended up taking ALL the ballast out the front, engines are Zenoha 38s, with solid stainless steelspinners made by me,

samparfitt

My Feedback: (43)

Thanks for all the input, guys: I always like lots of input.
Sorry to hear about the B-25 'augering in'.
Thanks for posting the link to your build pictures; looks like you did a real fine job.
Good to hear that yours was nose heavy: I'll still be making the FW an inch longer as I build heavy (ie, full cockpit, century jet pilots, gear/bomb bay doors, bomb drop, rotating turret) so it'll be easier to add several ounces to the tail, if need be, than 2-3 lbs to the nose. There's going to be around 17 air cylinders and also about 17 servos so I'm sure the plane will be around 50 lbs.
I've already done two planes with home depot duct tape so I'm comfortable with it. It comes 2 3/4" wide which covers most areas since rivets are used to hide the overlaps. I have two rolls of 6" wide duct tape but sparingly use it as I have trouble applying wide pieces of tape as parts of it usually stick where I don't want it to and then a new piece is needed. Panels are usually not exact widths of tape so a lot of waste is produced so the low cost duct tape is easier on the budget. I'm guessing a good 30% of my 'taping' is waste.

Fuse:
Crutch:
This crutch is not the 'normal' crutch where the 1/4" X 1/2" stringers run the full length of the fuse.
The wing is in the center of the crutch so there is a break in the center. The wing saddle WS-2 is used to connect the two ends of the crutch. I'm using an elongated wing saddle.
The plans have the top wing saddle attached if you want to remove the wing, which is removed from the bottom of the fuse. I'm not partial to putting large fuses on their backs to attach the wing as I can get hanger rash doing this. I'm opting to attach the wing from the top. The new wing saddle is 4" wide and runs from former F-2 (front of nose gear mounts) to the second former behind the TE of the wing. As you can see in the plans, since the bomb bay will be functional, there is little supporting structure on the fuse directly below the wing: thus the 4" wide ply. This also re-enforces the nose area where the nose gear is mounted. The aircraft ply is 4' long and I needed another 4.5" to run the full distance so I butt joined/with a 1" piece of ply sistered over the gap, and epoxied the two pieces together. The negative is that I'll have a removable top hatch over the wing which will give me some non-scale breaks along the fuse. I can live with this as with my P-61 and B-26, it's nice to easily remove the hatch and work on the receiver, air valves, etc, without having to access equipment from below the fuse. The original wing saddle is shown laying on the new wing saddle.

I used this same procedure for the Bates B-26 (and similar to my P-61) to strengthen the fuse. This should allow the nose and/or fuse from breaking off due to 'not so perfect' landings. Last season, I saw a large P-61 loose it's nose wheel and the entire front was ripped off from the nose digging into the ground. There was a large nose weight that fell out: I feel the nose damage was preventable if aircraft ply was used to strengthen the entire fuse (useful weight versus a chunk of lead). Also, last season, I ran into an 18" high dirt berm with my B-26 with minimal damage which, I think, was due to the air craft ply built into the plane.

The balsa crutch was pinned to the plans (with some wax paper over the plans) and the elongated wing saddle was epoxied to the balsa crutch. Cross members were then glued in to make the crutch rigid. The crutch is build upside down, in this case, so it will be rotated when the formers are added.
Some wood workers clamps were needed to hold the ply wing saddle to the balsa crutch while the epoxy 'cooked'. The cross members along the wing area had to follow the wing contour so they are not flush to the plans.

samparfitt

My Feedback: (43)

Wing:

Center wing:
(Last thing for the evening)
I taped the two wing spars together with the center spacer so they aligned over the spar in the plans.
Since I'm cutting new aircraft ply to replace the 3 ply spar, I figured that I might as well cut the whole spar as one piece. A fine lead mechanical pencil was used to trace the old spar to the new ply, including the new spacer. A band saw cut the perimeter while a scroll saw was used to cut the rib slots.
An oscillating sander was used to finish off the edges.

samparfitt

My Feedback: (43)

Aluminum tape:
A few more observations (may not be all scientific!).

Duct tape:
1. Doesn't wrap around compound curves very well: Sharp corners like wing tips are pretty good but large surfaces, ie front of cowl, wing fillets, require multiple pieces to cover: which is not scale.
2. Sticks very well to a FG surface: I've thrown many pieces away because I, incorrectly, got the initial contact wrong. 225 flights on my ziroli P-47 and the tape has never come off (and I've been to some pretty hot meets, meaning 100+ temperatures this summer!).
3. no orange peel look after application.

Manufacturer's scale tape.
I've never used this but just what I've read.
1. The tape appears to go around large compound curves very well, although it appears a lot of work is required to achieve this.
2. Not sure if all tapes are like this but I read that the finish has an orange peel and it must be sanded out.

And last, Gary makes top gun planes whereas I make sport scale planes.
His tolerances are higher than mine where his is very scale, where as, mine are 'good enough'.
I've seen pictures of manufacturer's tape on planes and they look great: I don't know if the builder's skill sets are better than mine (they probably are) but I'm happy with my 'duct tape' results.
==============

Fuse,

I pulled all the pins out holding the crutch to the plans and put the crutch on my 6" high risers.
I dry fitted the fuse formers onto the crutch.
Since I have a 4" wide ply running through many of the formers, slots had to be cut into some of the formers to be able to slide the formers onto the crutch.
The formers (F-2/3/4) hold the nose gear mounts so I re-cut new formers using aircraft ply.
Also, since I'm having a hatch over the wing, I still need to make some duplicates of the formers to construct the hatch ends.

Olsen

Hello again

Looks good Sam, and yes we all have our ways of doing things, I think like you if it looks good to me then I am satisfied.

I found these Tech. Notes on the Ziroli webpage [link]http://www.ziroliplans.com/ziroliplans/B-25%20LG%20plan.html#Tech Spec[/link] (all the writing on the plans are for the 101 inch version) and it says that the CG should be 6 inch from leading edge at fuse, and I have actually built in two hardwoodblocks with blind nuts so I can hang the complete model from my ceiling in a fishweight,at the right position and do the weight meassurement at the same time.
Perhaps Alanc can tell us where they ended up with the CG. otherwise I plan to balance mine as Ziroli says 6 inch back and Gear down.

Keep up the good work, and Best Regards Henrik

alanc

i will find out the full CG history for you, were it started, and where it ended up

Todd Jackson

My Feedback: (6)

This is what they list for the 101 in and the 118 is 6 inches back That is were I put mine for the 118 inch version but I have not flown mine yet.Todd.

B-25 Mitchell 101" Plan
Tech Notes
Stock Number
ZIR:B25101 B-25 Mitchell Technical Specifications
Specifications:

Scale: 1/8

Inches to the foot: 1.5" - 1'

Length: 78"

Weight: 28 - 36 lbs

Wing loading: 39 - 50 oz/sqft

Wing area: 1650 sq.in.

Wing span: 101"

Wing incidence at root: +2 degrees

Stab incidence: + 1 degree

Dihedral: 1/4" drop at wing tip, center section jig built

Power: (2) 26 - 38 cc gas

Washout at wing tip: 2 to 3 degrees built in with jig

Aileron throws: 3/4" up & 1/2" down

Elevator throws: 1" up & 1" down

Rudder throws: 1 1/2" to right & 1 1/2" to left

Flap degrees down: 40 - 50

Cowl length: 6 1/4"

Cowl height front: 6 1/2"

Cowl height rear: 8"

Cowl width front: 6 1/2"

Cowl width rear: 8"

Engine offset degrees: Right engine 3 right 0 down, Left engine 0 right 0 down

CG location: 5" back from leading edge at the fuse with gear down
Requires:

Ziroli cowls and or nose: yes

Ziroli canopy: yes

Ziroli plastic accessories: yes

Engine2) 26 - 38 cc gas

Spinner: (2)1" spinner nuts

Fuel tank: (2) 16oz square

Wing Tube: 1" X 24"

Control Horns: (2) 1", (2) 1/2"

Hinges: 14 LG flat hinges, 4 Lg hinge points

Covering: 1oz fiberglass cloth & epoxy resin

Retracts Main: yes

Retracts Nose: yes

Retracts Tail: no

Main gear struts: n/a

Tail gear strut: n/a

Air Kit: yes

Wheels Main: 5 1/2"

Wheel Nose: 3 1/2"

Wheels Tail: n/a

Radio channels: 6 or more

Servos: Flaps (2)150-200oz MGBB, Ailerons (2)90+oz BB, Elevators (2)90+oz BB, Rudder (1)120+oz BB, Gear (1)50oz, Throttles (2)50oz BB

MG-metal gear BB-ball bearing