rossmick

My name is H R Mickelson (Ross) and I have rejoined the RC community after having built many models when I was 16 - 20 ending with the Goldberg Senior Falcon which I still have and fly today. After 30 years in the USAF flying F-100s, F-105s, F4s and F16s I then flew MD80s for TWA/American and retired to work at Raytheon as a engineer. Finally, I really retired about three years ago and rediscovered RC. I bought new radio gear (JR11X), new servos, recovered the Senior Falcon, fired up the original Enya 60, joined a club, started flying and now am interested in building scale aircraft.

This thread will be my attempt to build the Ziroli 120" B-25 as scale as possible.

As I was new to posting a build on a thread, I tagged on to the B-25 build of Sam Parfitt, who has been very generous to me as I have posted my build on his thread. However, now I have come to realize that each builder should have their own thread, so I am starting this thread with the idea that many builders can add their build, suggestions, and constructive comments to improve what I hope is to create a winning scale B-25 B Doolittle raid aircraft. For those who are following Sam's thread I will repeat most, if not all, of my build posts to this thread.
As Sam can complete a build in a month or six weeks, I can see this project taking as much as a year to complete. There will likely be some redoes, tear downs, start overs, and delays as I try to figure out the next scale problem. There is certainly the possibility there may even be some basic building mistakes that have to be fixed, so I again encourage all constructive suggestions and additional information that you can add.

I have been following the 1/8 scale TopFlite Corsair Mods thread for several years and have my Corsair and all the mods just about ready for FG cloth. From the Corsair thread I have seen how many builders have contributed to the authors build and I hope the same situation can be accomplished here. Unfortunately, I started the B-25 without finishing the Corsair so I may do some jumping back and forth as I work on both.

TonyBuilder

My Feedback: (11)

HR, building is a proses of figuring out what works, even if you have done specific task sometimes it gets redone as other components come into the fray. I cant count how many times I had to redo something. Building a kit in its basic form (as per the design and manual) is much easier then a full on custom scale build. I don't know your skills (yet) but I can emagine a build like this will take well over a year, unless you come from the school of Sam Parfitt


Good luck with your build.


TB

chris923

My Feedback: (53)

Ross,

Good luck! We will be watching from the North.

rossmick

TonyBuilder

Thanks for the comments, I could not agree more. Sam is the IRON MAN - 18 hours straight with no breaks. That would take me 5 or 6 days to his one.
I'll let all of you decide my skill level, however, I consider myself an above average wood worker with an above average shop and supplies ( Can never have enough tools or supplies).
Looking forward to good advice and critiques. One really great thing about this sport is that you can learn something new everyday if you pay attention.

rossmick

Chris923

I grew up in Wauwatosa and graduated from Wauwatosa West in 1963, it is sure nice to hear from someone from your old home town. After high school I went off to Wichita for Aeronautical Engineering and then to the USAF for pilot training. Thanks for the best wishes. Today I moved the portable water cooler (swamp cooler) out of the storage shed and installed it in the shop. It was a toasty 106 today and anything above 105 is just a blast furnace. Oh, did I mention that there is zero relative humidity as well, until moving here I did not know that was even possible. Winters are great here, but the summers are really tough on this northern boy. Shop is down to a frigid 85 so I will spend some hours working on the design of the scale nacelles based on the FG cowl dimensions that came with the supplies. Looking forward to your suggestions and advice.

rossmick

I have received the plans and FG parts from Ziroli, kit parts from PCK, and as with my Kellogg TBF, the parts are really great. I went with the Sierra Giant Scale gear with wheels and brakes (the gear are a work of art). I will have the gear converted to electric as I normally shoot many touch and goes.
I also bought two new DA 50s. I finally decided to follow Sam Parfitt's lead on the larger engines as I was not comfortable with the 38cc idea and the comments from other builders of the B-25. As I live close to Tucson, and know the folks at DA, I decided to use their product.

From 'Tevans55' I got this information - I have a B-25 with a Jet Tronics air valve that eliminates the servo and manual air valve. It is electronic and takes up very little room and makes your brakes work very smooth. They work like an anti-lock system. You still need the compressed air but it is a very nice system and easy to install. http://www.jet-tronics.de/Brakevalve.html.
Also from 'Tevans55' - I have used Ram and Electrodynamics lights in my B-25's and I much prefer the Electrodynamics lights. The landing lights are much brighter. Hope this helps. http://www.electrodynam.com/store/SunVis.html

I had Century Jets convert my Sierra Precisions Ziroli B-25 landing gear to electric. The controller handles a separate power source (7.4 v), has options for 2 gear or three gears, does door sequencing, landing light and delayed left gear options. I tell you the price is right. To see a video of a test jig I built for testing go to http://1drv.ms/1cRzCSI.
Notice the landing lights coming on when the gear is down. All appears to function as advertised and does not draw that much power. Can also be found on You Tube at http://www.youtube.com/watch?v=7S4f5...ature=youtu.be

rossmick

I must give credit to Sam Parfitt as his build, suggestions and comments have me started on the right foot.
Most of this list is a copy of Sam's list with changes for my build.

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.
Sierra Precisions gear with wheels and air brakes - Darrell has real nice 6" B-25 wheels with brakes.
Ziroli plans which are blown up 101" B-25 plans with 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.
Scale mufflers
Cements - Carpenters glue will be the glue of choice for the bulk of the plane but epoxy and Aeropoxy will be used on critical stress areas..
Servos - Hitec HS-645's and other smaller servos.
Each of the four flaps will also get their own servo
Cockpit - Dynamic balsa kits are being used for the cockpits and century jet pilots will be used.
Covering - FG cloth with finishing resin and 2-part epoxy primer with panel lines and rivets.
Finish will match the B-25B paint used in the Doolittle raid.
Center wing will be made removable and the bomb bay doors will be functional, 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.

TonyBuilder

My Feedback: (11)

HR, nice start. May I suggest that you post larger files on your pics. They are very small, not much bigger then the thumb nails. Makes it hard to fallow your build. Anyways I am looking forward to your build.

TB

rossmick

TonyBuilder

The photo size is a surprise as they show up larger on Sam's thread. I'll go back and see if I can edit the post to get them to show at a larger scale.

I went back and saw that I had two different file sizes and remembered that my first attempt to include photos were too small. Of course I picked them instead of the larger, The photos show a larger size now. If they are still too small let me know and I will resize them and do another down load.

Thanks

rossmick

Getting started on the B-25 even though the Corsair is not quite finished, I could not wait any longer. In studying the plans I was not certain of their accuracy as many items did not match up from one view to the next. Also the center line on the top view for the crutch layout was way off so using it to build the crutch seem problematic.

I know Sam and others pulled off the crutch build just fine, but their talent and experience are way above mine so I decided to build a simple jig that I could be certain of the center line and height. I had an 8' piece of 1" MDF so I used it as a base, I laid out the center line and station/ former lines and then built the jigs to set the height and width so the formers could be clamped in to position based on an accurate center line and height. Note, that the jig plates are held above the angle by 1/16" so they can be squared.

All lite ply formers are dry fit and clamped, looks like slots will have to be recut for stringer alignment. Did find that F1 was broken in the box. Now to start re-cutting formers with aviation ply and Sam's beefed up center crutch. I am a massive over builder so I will follow the majority of Sam's recommendations on a stronger structure due to using the DA 50s. I have decided to build the center wing section semi attached to the fuselage so the aircraft can set on all three gear for storage and transport, also I think the structure will be stronger as well. I like the full size idea of fuselage built right in to the wing as a module. I plan to double the formers here and when they slide in they will be bolted together with bolts and blind nuts just like the full size plane. May still use the bolt down system from the plans as well to ensure structural integrity.

I just had to build the jig. I was a tool designer at Boeing while I was going to Aero Engr. school at Wichita State so the jig just makes sense to me and worth the effort. As my next plane will be the Kellogg Avenger, which uses the crutch design as well, I should be able to re-use most of the jig. I really like this set up as I can more easily see and work with the mods that will be required for the gear and other required changes before I apply any glue. Notice the fuselage is inverted in the jig at this time but will be rotated to work the top of the fuselage leaving the lower section open for modification. The jig sections will have to be modified to accept the fuselage mods when turned over.

tevans55

Hi Ross-
You know I'll be watching. I have a Ziroli B-25 in my future...when I retire and have the time. Are you using the Century Jet electric conversion retracts in this plane?

LOVESCALE

My Feedback: (3)

Looking forward to seeing. Down the road from you in sahuarita

rossmick

tevans55

Besides watching I am looking forward to comments and suggestions. Yes the gear is converted to electric by Century Jet. I am just not in to the pneumatic gear although I will need one air tank for the brakes.

rossmick

I somehow managed to omit the B-25 B from the thread name, fat finger I guess. I am hoping that the thread name can be changed, but it does not look promising. I may have to start over with a new corrected thread name and somehow delete this thread, but right now I can't even figure out if a thread can be deleted.

chris923

My Feedback: (53)

Ross,
I live, get west of Timmerman field in a Townhouse built in 1970. When was the last time you were back in the "frozen Tundra"? When you finish your build, stick it in a trailer and bring up to Fond du Lac for Warbirds over the Midwest!

LOVESCALE

My Feedback: (3)

Hey Ross,
yes. Will help out anyway I can. Send me pm if you ever need assistance. I'm currently getting ready to build the z-corsair. Got the long kit and going to build my own fuse. Just ordered the electric conversion for the retracts. Not big fan of air. I fly at sam1191. Come visit.

tim

hkgdcshu

HR, building is a proses of figuring out what works

rossmick

Chriss923
My grandfather paid for my very first airplane ride (Cessna 172) at Timmerman field when I was 12. I also belonged to the Civil Air Patrol Squadron at Timmerman when I was in high school - small world.

Last time back was about 10 years ago, my brother and sisters have all moved out to Florida, and parents are gone, so there is not too much reason to return.

Once I get squared away on the scale flying/warbird events it would be a real kick to get up to Fond du Lac. Looks like a larger trailer will be required but I want a really light one so I can pull it behind the 5th wheel. I have a Dodge 3500 dually diesel so pulling is not a problem, but with a 36 foot 5th wheel I am not sure of the total length restriction. We really like our 5th wheel so trading it for a toy hauler with garage in the back is not an option right now, It would be great to get back to Wisconsin but only in the summer time, I still remember those winters. Took my wife up to Wisconsin one winter to visit my Mom and she got cabin fever one night and had to go outside. I reminded her it was -20 degrees and she said she didn't care - she got about 30 feet from the house and had to go back inside. As it rarely gets below freezing here she just didn't realize what -20 was all about.

rossmick

Lovescale

Thanks for the support, I will count on it. Good luck on the Corsair. I have seen too many gear up landings with the pneumatic system when the air ran out, as I said, I like touch and goes. I have been to Sam's field and there sure are a nice bunch of folks out there. I hear you guys are getting moved, any truth to that? I will make it a point to load up my John Deere (modified Ugly Stick) and come on out one of these weekends. Is Sunday better that Saturday? Look forward to meeting you.

rossmick

hkgdcshu

I sure agree with you on that. I have gone through 5 different versions of adjustable cowl flaps on the TF 60" Corsair, problem was that it really stopped my build on the plane as I got so frustrated. I have a working system now but am still not totally satisfied. One thing I have learned is it is much easier to go scale on a larger model, just getting the main gear door linkage installed on the Corsair was a real task as the space was so small.
Look forward to getting your comments and suggestions.

LOVESCALE

My Feedback: (3)

Ross
I'm usually there Sundays and Saturdays. If I'm not working Saturday. Not going to be there this Sunday. Yes I heard tonight that the bond is moving forward to build a new site for us and trcc back to back. But you know how that goes in this town.

But it like to meet you too
tim

chris923

My Feedback: (53)

Ross,

I am currently teaching one of the Adult CAP er's to fly Rc. I hope to see you and your plane here in the future.

rossmick

Well surprise, surprise, when I created a new thread the system went back and copied the original thread in to the new thread name. Nice but unexpected.


So here we are.

rossmick

I had Century Jets convert my Sierra Precisions Ziroli B-25 landing gear to electric. The controller handles a separate power source (7.4 v), has options for 2 gear or three gears, does door sequencing, landing light and delayed left gear options. I tell you the price is right. To see a video of a test jig I built for testing go to http://1drv.ms/1cRzCSI.
Notice the landing lights coming on when the gear is down. All appears to function as advertised and does not draw that much power. Can also be found on You Tube at http://www.youtube.com/watch?v=7S4f5...ature=youtu.be

rossmick

One of my goals for this build was to, as close as possible, build to scale so as to be able to compete in contests, however, with my research, I find that the plan needs considerable revision. Unfortunately, the suppliers of the major components built their product based on the plan. An example is a requirement of a 12 degree forward slant on the nose gear with a 110 degree closing sweep, also a 4 degree forward slant on the main gear with a 115 degree closing sweep, the plan is no where close to these requirements. The plan shows a 85 degree closing sweep for the main gear which can not be adjusted for to meet scale requirements. Maybe the fact that the gear is no where close to these requirements does not bother some but it is unacceptable to me to meet my goal. Builders like to build, and I rushed in to the build, so lessons learned here is that much more time should have been spent studying the plan to the scale requirements and then order the parts cut and components specifying the correct requirements.



'Necessity is the mother of invention' so it is said, and after thinking about how to handle the gear situation I decided to "Do it myself". It was not my first notion to modify the gear myself as they are expensive and a really quality product, so I though let the manufacture do the work. After some delay I rethought the situation and starting looking at what it would take to change the slant and closing angles on the nose and main gears.

First, I looked at the nose gear and realized that the open slant could easily be changed without destroying the gear. Sierra did an outstanding design here, and it was straight forward to loosen screws and reposition the slant on the open position. The only issue was that the electric motor mounting block had to be filed to allow for clearance with the new gear position. As there was plenty of material on the mounting block it was not too difficult to file off the required amount. Now I have the 12 degrees required for scale, and additionally, now I was convinced I could handle the mains.

Now for the mains, it became clear that the cam slot would have to be changed to get the extra 10 degrees required for the scale plane. I mapped out the travel path and the down lock location on paper and set there for a while and wondered if I would destroy the gear or get it to work, a mistake here meant considerable cost and an extreme time delay. I could also see that it was a two step process, first, to file out the additional path, and second, to make a down lock plate to hold the cam locked as filing out would leave a large gap eliminating the lock capability. Finally, I grabbed the files, marked out the path and started filing. Little by little, working both sides, I worked my way out, testing as I went. First 5 degrees, then 7, then 10. Now for the down lock plate, file and test seemed the best approach. My beautiful machined gear was no longer so beautiful, however, the gear now opened the additional 10 degrees and moved up to the lock position. Building the lock plates just took more trial an error to get all the bolt holes and the lock position to line up. It's not as clean but it works. I allowed addition height above the cam for more strength on the lock plate so it sticks up above the rail structure. I could have relied on the drive screw to hold the lock position but did not want to put the pressure of the touch down on the threads. Additionally, I am certain the lock plate is required as the upper portion of the cam travel has to be there to hold the cam down in the slot.

Photo 1, new nose gear 12 degree position, 2-3, original main 85 degree position, 4-5, the new main 95 degree location. I would recommend that if you want scale gear, and you use the Sierra gear, that you order the main gear with a 95 degree dimension and save a lot of work, and have a much better looking gear structure.