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Old Dec 31, 2012, 12:00 PM
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Castel101's Avatar
United States, OR, Portland
Joined Sep 2011
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Great work on the retracts, they look great! I had a question though, maybe not important, but shouldn't the spring portion (circular bend) on the spring wire, between the retract and the strut, be facing along the back instead of sideways? This so that the spring takes any loads that occur in the direction of travel like bumps, grass if going off the runway, and etc. As it is it helps for lateral stress which is not frequent to occur. Just wondering?
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Old Dec 31, 2012, 01:32 PM
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PeterF's Avatar
United Kingdom, England, North York
Joined Nov 2004
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Quote:
Originally Posted by Castel101 View Post
Great work on the retracts, they look great! I had a question though, maybe not important, but shouldn't the spring portion (circular bend) on the spring wire, between the retract and the strut, be facing along the back instead of sideways? This so that the spring takes any loads that occur in the direction of travel like bumps, grass if going off the runway, and etc. As it is it helps for lateral stress which is not frequent to occur. Just wondering?
Castel101,

This gave me some thought during the build, the retracts are set up currently how they came out of the box. I wondered if this was for sideways retraction rather than forward and backward as in my model. I did turn them through 90 to start with and installed them like this but then I had one of those "Oh **** !" moments because the spiral moves the leg about 1/4" (6mm) offset from the centre of the retract unit the wheel trucks came too close to the openings I have cut. This was soemthing I completely missed when I was putting everything together as I focused on the position of the hole in the retract not the wire. Really I was then faced with some difficult decisions

1. Cut the doors wider and add the thin strips onto the other side of the hatch and onto the doors.
2. Recut the mounting plates.
3. Rotate the wires back to the positions they now have.

I chose the 3rd option after I had tested the wires to see how easily they bent in either direction and I found that there was very little difference. In the direction I currently have them two portions of the spiral are bending in torsion so there is some give.
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Old Dec 31, 2012, 01:38 PM
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Originally Posted by AIR SALLY View Post
the real ones had to have the main doors modded to open a few degrees more also ....as when turning tight while taxing the trucks would twist and the wheel balance lugs would hit the door.yeah i always am looking at that clam shell door to see how they hinged it.the front hinge is different than the rear one .yeah your on your own when you start modding stuff .but you are really doing a great job .....im just being too scale crazy due to being so close to the plane.....one of the reasons i have not tried to build one yet
I understand the reservation you have about tackling a model of this, you really would be your own worst critic.

I love these little stories like the door opening. My father worked in the aerospace components industry before he retired (as did my Grandfather) and has numerous stories such as working on one civil airliner on the flap drive mechanism and having splined drive rods dropping out of gearboxes as the wing flex was somewhat greater than the splines due to some miscalculation or incorrect specification.
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Old Dec 31, 2012, 01:54 PM
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United Kingdom, England, North York
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A quick update to show how I have solved the problem of the wheel bogies not lifting fully into the wheel well. I have not made any changes to the retracts but have added an angled plate to the top of the wheel well so that as the truck enters the wheel well, the front wheel touches the angled plate and runs forward, rotating the bogie to raise the rear wheel higher up. The front wheel moves further forward than the opening in the hatch.

I came up with this solution when I awoke at 2.00am last night. This must have been playing on my mind.

RC B2 stealth nose leg retract test from below (0 min 10 sec)


RC B2 stealth nose leg retract test from above (0 min 9 sec)
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Last edited by PeterF; Dec 31, 2012 at 02:17 PM.
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Old Dec 31, 2012, 02:15 PM
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Great work, I totally get the spring orientation now, I didn't think about the offset. Looking good!
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Old Dec 31, 2012, 05:44 PM
A-4 nut!!
skyhawk's Avatar
Vancouver B.C.
Joined Apr 2002
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I don't - you still need to rotate the strut 90 degrees.
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Old Jan 01, 2013, 02:59 AM
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Originally Posted by skyhawk View Post
I don't - you still need to rotate the strut 90 degrees.
Skyhawk,

I checked the fex of the strut with the spiral section at 90 to the spiral as I currently have them installed and it seemed to be as flexible as in line with the spiral - this was my only justification for avoiding rework. This is the first time I have used this type of retract.

Can you confirm that it is absolutely essential to have the spiral in line with the direction of the wheels and I will then look into what work is required to achieve this.

Thanks for your advice.
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Old Jan 01, 2013, 10:42 AM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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nice easy fix for the boogies. if the wie wont work like you have it you could always fine some spring suspension struts..but what you have should work for a few flights anyway.
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Old Jan 02, 2013, 04:13 PM
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United Kingdom, England, North York
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Rotate the main gear struts

The work involved cutting the gear doors 1/4" over and remaking some of the mounting plates, rotating the leg was the easy part.

I guess I should have done this when I first noticed the problem rather than trying to get by. Live and learn which is the good thing about the forum, thanks to everyone who noted that I had them the wrong way around.
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Old Jan 02, 2013, 04:21 PM
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Castel101's Avatar
United States, OR, Portland
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Looks good Peter! Any longitudinal loads would rest on the coil spring now which is good for your retracts and mounting plates. Can't wait for more updates and maiden .
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Old Jan 02, 2013, 11:13 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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try using offset hinges ....you may need to remove the factory pins and use a long piece of piano wire so you can have all the hinges on the correct centerline. the full scale uses a offset type of hinge.the curved doors is what causes the proplems.
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Old Jan 05, 2013, 01:40 PM
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United Kingdom, England, North York
Joined Nov 2004
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Elevon Servos

Completed the elevon servos using Hitec HS-85 mini servos. There is little detail of these on the plan so I just copied the hatch design from my Top Flite DC3. The skin sheeting is 1/16” (1.6mm) thick and the servo hatches are from 1/32” (0.8mm) ply with doublers at the front and back so the hatch sits flush with the skin. ” x 3/8” (6mm x 9mm) strip wood blocks are then glued onto the inside of the skin for the hatches to sit against and for the small No2 screws to screw into. Nothing novel and makes a very workable solution. Make sure the strip wood blocks are glued to something firm such as adjacent spars or ribs, not just the balsa sheet.

The most fun (?) has been sorting the programming of the elevons as they have elevon differential (sort of like aileron differential but acting on elevator as well) with much less down travel than up travel. Got it all sorted in the end. I have a Hitec Aurora Tx and one thing I like on that is that for example you give the aileron travel 100% and elevator travel 100% you can also limit the mixed travel (to say 120%) so it does not try and move the surface more than required when you have aileron and elevator at the same time.
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Old Jan 16, 2013, 04:44 PM
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Joined Nov 2004
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Drag Rudder Servos

Completed the drag rudder servos using Hitec HS-85 mini servos. There is some detail of these on the plan showing the neutral openings and the fully open and closed positions. The push rods are internal which has made a little more work but it does mean that they are out of sight, an external set up looks a little unsightly on the upper surface even if it is more accessible. Given the available servo travel I can actually open the servos more than the plan requires. Interestingly the plan shows that the upper section is always more open than the lower section, therefore it has a sort of reflex setting. The hatches follow the same detail as the elevon servos. Now I have done this I am wondering about going back to the elevons and seeing about setting up a less visible pushrod system.

The programming has been equally involving given I can have extra travel on the opening than closing directions, a sort of drag rudder differential action. I have set the mixing up so the slider on the Tx can open both drag rudders more to give more yaw stability and also when the landing gear is down they are opened more. Not sure if these latter points are required or not. I have put the nose wheel steering onto a different channel mixed from the rudders but without trims linked through and have put the nose wheel steering trim onto one of the additional trim buttons. Therefore I can trim the steering and rudders separately.
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Old Jan 16, 2013, 05:56 PM
check for reversed controls
alpea 41's Avatar
United States, CA, Chino
Joined Oct 2007
10,206 Posts
Nice work watching with interest
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Old Jan 16, 2013, 10:24 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
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im not sure you need that much .....thats what they look like when the speed brakes are out .
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