Building a Ziroli B-25(CONDENSED VERSION)  
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Building a Ziroli B-25(CONDENSED VERSION) - 2/1/2002 7:14:15 AM   
mselby



Posts: 372
Joined: 12/29/2001
From: Bangkok, THAILAND
Status: offline 		guns are easy. aluminum tubing, a little time on the drill press for vent holes, balsa foam for the gun housing.
Mike

(in reply to badigital)
       Post #: 26

Building a Ziroli B-25(CONDENSED VERSION) - 2/1/2002 7:37:12 AM   
RandyL


 

Posts: 366
Joined: 2/1/2002
From: Silver Lake, KS, USA
Status: offline 		Enjoying the thread. I am in the process of building the 101" version myself. My venture is being logged at.....
http://flyinglindy.homestead.com/b25construction.html
I sent my Ziroli guns back.. they were _way_ to small for the proper scale. That is not to bad mount Ziroli...they have all been very kind to me and helped a lot.
I have stayed with the bellcrank rudder system and it seems very tight so far. I solder all the clevis and do all drilling with wire guage bits for a snug fit. Ball links finish the setup at the rudders so no wear takes place on the wood control horns. My approach is to build the airframe with the absolute least amount of servos ( and wiring ) that is possible. Hoping for the least amount of failures this way... The KISS method if you will. You all have some great ideas and good looking aircraft!
I hope to have an airplane by June or so if all goes well.

Randy

(in reply to badigital)
       Post #: 27

B25J - 2/1/2002 9:39:53 AM   
Big_Bird



Posts: 3237
Joined: 12/18/2001
From: Arlington, TX, USA
Status: offline 		I've really enjoyed this thread. Lots of good info. Here is a photo of the one I built and flew.
Ken

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(in reply to badigital)
       Post #: 28

Zowie - 2/1/2002 10:52:00 AM   
badigital


 

Posts: 20
Joined: 1/18/2002
From: Jefferson City, MO,
Status: offline 		You guys are to hard on me! Remember I am getting old and feable. Let's set the record straight girls, ( you LORCS know who I am talking to ) a forum is for what, discussion of ideas. Save the ridicule for Ed Jones (hehehe) I have honestly got to say that this forum has achieved input beyond my wildest dreams. I am sure now that whomever reads this forum will get all their questions answered. Allot of good ideas and different techniques have passed, isn't it great. You know this whole thing would have been easier for all of us builders if Ziroli would revise their plan. Not to knock Ziroli of course.
Steve this is why we have these discussions at your field so we can instigate it here! It sounds like you done things well, I am however still concerned about the fuel tanks in the fuselage though! I guess you will have to prove me wrong, I will be anxious to see it roll without the 1.80's coughing. I will make it the workshop some night to see the bomber group!
Ken, that is pretty I really like the scheme you have chosen. I am going to use the scheme for Executive Sweet. She can be seen here http://www.accesscom.com/~nchinn/air1.html If anyone has other pics of her please send them to me?
Mike and Ken how do you have your mixing setup for landing?
i.e. 20% flap and 5% down elevator or what? Where is a good rule of thumb to start with? With my radio I have a landing switch and can utilize it, is this what you guys have done?
Concering props is a 10 pitch a little to much for landing approaches? What I mean with this is will the plane be carrying to much energy to set in nicely?

Thanks

(in reply to badigital)
       Post #: 29

B25 - 2/2/2002 2:21:38 AM   
gibb


 

Posts: 108
Joined: 1/26/2002
From: Livonia, MI, USA
Status: offline 		I think your nervousness about flying this bird is too overblown. It is really easy and gentle to fly. Just keep the wings level and it flys like a heavy trainer. If you can add weight to a large trainer in G2 and cut the control throw down, that should simulate a B25. As I said before, just don't make the plane heavy.

By the way, where are all of you from? I'm from the Detroit, MI area.

Jim

(in reply to badigital)
       Post #: 30

Building a Ziroli B-25(CONDENSED VERSION) - 2/2/2002 5:12:50 AM   
Big_Bird



Posts: 3237
Joined: 12/18/2001
From: Arlington, TX, USA
Status: offline 		karben, I've put many first flights on my aircraft and other peoples planes and I have to say that the B25 is just about the easiest to fly of all of the big birds. To land use at least 30 degrees of flaps, keep the nose sleightly down in a gentle approach with about 15% power on. As you start your flare reduce throttle slowly and settle in on the mains. If a big heavy plane could be a "dream plane to land" this has to be it. Don't be afraid to apply a little power if you need it. Your #1 priority should be to have a pair of engines that don't quit and are balanced. If one quits on you at the wrong time, all bets are off.
Good luck,
Ken

(in reply to badigital)
       Post #: 31

b-25's - 2/2/2002 5:33:26 AM   
1wolf-RCU



Posts: 190
Joined: 1/4/2002
From: camdenton, MO, USA
Status: offline 		Hi Gibb
I'm from Camdenton Mo. a friend of mine TJ and I have the skunkworks plane shop that Ben mentioned we just like to build planes. Don't let Steve and Brian's little bickering bother you the rest of us are pretty nice guys As for them it's just a byproduct of having 2 salesmen in one spot. I hear they are OK if you keep them seperate. We are thinking of having a time out corner at the field if they don't start playing nice with the other flyers. Anyway back to reality Have really enjoyed your suggestions on the B-25's. The Tank situation Brian is referring to is this ... We are using the 1.8 rcs with the rear mounted carb, ignition, throttle servo, and battery all in the nacelle (we wanted the system as isolated as possible to eliminate the possibility of interference) we ran out of room for fuel tanks sooo we located them in the fuselage just ahead of the wing thinking with the pump and reed valve setup on the rcs the distance of the tank ( aprox. 18" of fuel tubing) and being slightly higher than the engine wouldn't be a problem for the pump and and the diaphram would stop any tendancy for syphoning. The engines with their servos and ignitions are each built as a module so they can be tested and broke in as a unit. We were going to go with 2 degrees right thrust on the right engine and 0 on the left. Any thoughts or comments on this setup??? pics are on the website of the project at [url]www.skunkworks.rcplanet.com[/url] Thanks again guys for your previous advice Glenn

(in reply to badigital)
       Post #: 32

Building a Ziroli B-25(CONDENSED VERSION) - 2/2/2002 7:38:22 AM   
mselby



Posts: 372
Joined: 12/29/2001
From: Bangkok, THAILAND
Status: offline 		badigital,
This thread had turned out to be rather interesting. On flaps I use 40 degrees with around 4 degrees down elevator. However, when the plane is up high enough trim your down elevator mix on the radio for level flight so that the sink rate is controlled by easing the power back. Take off flap setting is around 18 degrees, (no magic on that number its just where I set it)
250 feet on grass for landing is tight but workable. you need to be careful.
my props are 16.5 x 11 which mejzlik made for me, 10 pitch should be fine, again it is engine dependent.
Mike

(in reply to badigital)
       Post #: 33

B25 - 2/2/2002 11:57:02 AM   
gibb


 

Posts: 108
Joined: 1/26/2002
From: Livonia, MI, USA
Status: offline 		Thanks guys for the MO insight.

I'm surprised that MSELBY needs so much flap.
MY Z- hellcat needs significant amounts of flap at 37 lbs to land , but my 30 lbs B25 could slow down easily without them. Remember, over 10-15° and you will lose lift and increase drag.
I also add a bit of elevator trim when the flaps are down. I just mixed it in and use a switch for both.
For calm wind:I use about 15-25% throttle on final and then just reduce toa tick over idle as I cross the end of the field. Then at about 2-5 feet above the ground, I cut the throttle and let it sink in.
For 10-20 mph head wind: same power on final leg, then reduce and hold to about 10%until touchdown.
The one bad thing about the 25 is that in strong winds, you really have to fight the roll. Especially with the smallish ailerons.

My buddies and I are heading to the IMAA rally of Giants this year at Muncie. Are you guys attending? Would be good to have a formation flight.

My club field is about 750 feet too. Only need about 300 though. If you want a test pilot, Id be glad to fly them all.

The tank in the fuse is an interesting one. I would think that the carb could pump without problems, but I sure would test it first outside of the airplane by mocking the exact location. Then I would raise the whole thing to simulate a take off and check at full throttle. Once again, idle and low throttle sync is more important than full throttle.
By the way, where did you install the fuel tanks? Theres not much room in the fuse either.

(in reply to badigital)
       Post #: 34

b-25's - 2/2/2002 12:47:46 PM   
1wolf-RCU



Posts: 190
Joined: 1/4/2002
From: camdenton, MO, USA
Status: offline 		we mounted them between the two formers just in front of the wing. We lined the bay and fuel proofed it then slide in 2 16 oz tanks side by side. We are going to test the engines with an additional 12 inches of fuel line just to make sure we have some safety margin. The Muncie thing sounds good. If badigital has his ready we could bring up 5 that would be pretty neat. Do you know about when it is???

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Building a Ziroli B-25(CONDENSED VERSION) - 2/2/2002 4:42:00 PM   
mselby



Posts: 372
Joined: 12/29/2001
From: Bangkok, THAILAND
Status: offline 		Gibb,
I could probably get away with around 30 degrees flap, but I find the plane doesn't slow down as much as I would like. I prefer to continue to carry power on approach to avoid mushy ailerons. There are some climate effect differences in the tropics as well. You certainly don't have lift with 30 to 40 degree flaps, but for landing you are not looking for lift.
Mike

(in reply to badigital)
       Post #: 36

thrust??? - 2/2/2002 8:02:01 PM   
1wolf-RCU



Posts: 190
Joined: 1/4/2002
From: camdenton, MO, USA
Status: offline 		the rear carb is what made everything more interesting. If you shorten the nacelle by moving the firewall back the ziroli cowls are too short and if you don't the engine sticks out an inch and a half too far so we made an inset into the tank are for the carb to fit into this had too be large enough to accomodate the air intake requirements of the 1.8 As we are building 4 we are building as many things modular and interchangeable as possible so we can "mass produce " them at other stations then put them in the plane later such as the engine modules, access panels, turrents, and so on. Any comments about the thrust ?? what did you guys do??

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thrust - 2/2/2002 8:03:12 PM   
1wolf-RCU



Posts: 190
Joined: 1/4/2002
From: camdenton, MO, USA
Status: offline 		another mount pic

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       Post #: 38

Building a Ziroli B-25(CONDENSED VERSION) - 2/2/2002 8:32:25 PM   
selpel



Posts: 52
Joined: 1/31/2002
From: Sunrise Beach, MO, USA
Status: offline 		Hey Glen, Post the photo of our hatch assembly the one with the panel laying on the wing. I thought these guyes may have a comment on it. Steve The Prez.

_____________________________

The Prez.

(in reply to badigital)
       Post #: 39

hatch - 2/2/2002 10:14:46 PM