Posts: 110
Joined: 3/28/2007 From: Simpsonville,
SC, USA Status: offline
I understand what you mean about the push/pull nose gear. I've been wondering about that myself. Looks like Spring Air retracts are the way to go as they don't use a push/pull system on there gear. I believe a firewall retract mount is best suited for this model Prop-Jet. Please view post # 1686, Page 68 here in this forum. There are photos of a Bobcat with a Firewall mount retract installed. This model retract will provide a better sterring method then the Robarts model Push/pull system as the Spring/Air sterring controls are internal to the fuselage.
View the Spring/Air web site for model 101- Firewall mount $149.00
Posts: 1203
Joined: 9/14/2006 From: Fort Washington,
MD, USA Status: offline
Here's are pics of my issue with the front/noser gear retract with strut (2 pics to the left). My main retracts are fine as you can see in the pics (pics to the right).
The issue is the pull-pull control arms can't go any further down the strut to clear the mounting rails. If you look close you can see the mouting in the pic to the far left.
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Posts: 110
Joined: 3/28/2007 From: Simpsonville,
SC, USA Status: offline
Hello Boomerang1 Yes, That arrangment is a good idea to keep the servo close to the retract, I'm still in a pickle trying to figure this all out. I would really like to make use of the mounting rails that are alrady there and I would, but it's still the problem with the steering. I don't want to use the push/pull system. I want to have the steering system like your using. Looks like I'll hane to cut out the retract mounting rails and the most of one bulkhead and relocate the Wall mount retract to the foward bulkhead to make this all work correctly.
I have added a couple of photos of my Bobcat and my idea of cutting out the center section of the aft retract bulkhead leaving only a plywood ring behind for reinforcement reasons. Then add & glue a piece of 1/4" thick plywood to the forward retract mounting bulkhead and install the firewall retract at this position with the servo attached if one like to do that option.
Anyway that's my plan. I know it seems like it's a lot of work, but this is how it should have been designed from the beginning for steering reasons only. This is just my 2 cents worth.
< Message edited by sbrackets -- 7/27/2008 2:56:46 PM >
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Joined: 12/6/2001 From: Beavercreek, OH, USA Status: offline
If you have the access, what I did was laminate ply to the area under the control arms and then hollow grind the mount away for clearance. Hopefully the pictures are clearer than my description . This was a mockup I did before to make sure the idea worked before butchering the gear mounts in the airframe.
< Message edited by RAMFlyer -- 7/27/2008 6:50:16 PM >
Posts: 110
Joined: 3/28/2007 From: Simpsonville,
SC, USA Status: offline
Hello Ramflyer Thanks for offering your ideas. I guess the bottom line is, theres no easy way to install a good steerable nose gear on this bird without a good deal of work in front of you All I know is that you better a your Dremel tool ready!
Posts: 60
Joined: 12/19/2007 From: oviedo,
FL, USA Status: offline
quote:
ORIGINAL: HeliTB
(tilt the prop side down).
YES!! We flew ours without the downthrust at first. Takes a lot more runway to get it off the ground. With the downthrust, you will cut your runway usage by 1/2 to 2/3. It flys much better with the downthrust.
Take a look at a BVM BobCat or KingCat witht the turbine.... they both have a good bit of down in them.
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Joined: 6/24/2005 From: Sydney, AUSTRALIA Status: offline
sbrackets, the guy that originally built mine used the servo mounted on the retract because he made the noseleg retract forwards so a pull/pull setup would have made the cables go tight, not loose when the wheel retracted.
I notice on yours the wheel retracts back so a pull/pull system would work fine. I did what HeliTB suggested on my other jet, dremmelled out a trough for the retracted steering arm. - John.
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Posts: 110
Joined: 3/28/2007 From: Simpsonville,
SC, USA Status: offline
I really am not familiar with how the Push/Pull cable system works. I have always use a 2-56 control rod for steering in the past. I understand how it works, but I don't have any experience with them. Just wondering about all that loose cable getting knotted up on something inside the fuselage during flight.
Do you guys believe that I'll be OK if I order the retracts with the push/pull system for the nose gear? Rather then going through all the trouble of a firewall type like I was planning? I really hate to make this build more difficult then at has to be. Your advise would be greatly appreciated.
P.S I would really HELP! if someone would post photos of their Push/Pull nose retract with the cables in place with the gear up, and the gear down so that I could view the cable arrangement.
< Message edited by sbrackets -- 7/28/2008 12:18:30 PM >
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All Forums >> RC Airplanes >> RC Jets >> RE: Nitro models pusher Bobcat? 
RE: Nitro models pusher Bobcat? - 
. This was a mockup I did before to make sure the idea worked before butchering the gear mounts in the airframe.
