Need a Profile, 20cc gas
#26
Member
Thread Starter
The questions continue. I am ordering a short kit of the MoJo 65 from Lasercut USA today. I need a bit of help with two questions. First, should I order the fiberglass tubes for the fuse as noted on the plans, or get carbon fiber tubes? A bit lighter, and more bucks. Second, what do I use for landing gear legs? Is there anything appropriate available commercially?
#27
My Feedback: (2)
I'd order the fiberglass tubes. The plane is already a fly weight with an absolutely ridiculous power to weight ratio. I generally save stuff like the gear when a plane goes in hard, but if I needed a set, bending up and drilling a set from flat stock purchased at a hardware would be no big deal.
#28
Member
Thread Starter
Thanks Mr. Hicks. I agree with using the fiberglass tubes. Think I'll use an aluminum wing tube, and bend up some landing gear from 6061 aluminum flat stock. The fellow that owns LasercutUSA does a beautiful job cutting the MoJo 65. A flying buddy of mine has one of the short kits, and I looked it over yesterday. As nice a cutting job as I've seen in quite a while. Can't wait to get one of my own.
Larry
Larry
#29
Member
Thread Starter
Flight control hardware?
Can any of you folks that have, or are, flying a 65" profile recommend servo sizes and servo arm lengths for the airplane? I'm guessing 250-300 oz-in torque, and maybe 1 1/2" servo arms? I'm intending to use Dubro-style machine screw control horns, likely M3 size. Thinking about using Pro Modeler mini sized units that support HV and high torque. Think these might help shed a few ounces behind the CG. Thoughts, recommendations?
#30
My Feedback: (9)
Larry on my 72" Fusion I'm using a 330oz on the rudder but only 230oz on the elev and aile. I do have 2 elev servos so if you are using 1 I would increase. I also use the Du-Bro arms. I think they are 2" with 4-40 rods and ball links. I just use one battery for everything. It's a 3300 LiFe. I can get 3-4 flights on it. No problems with this set up so far.
I switched engines last week but haven't got to fly it yet. I had a DLE20 on it and switched to a Valley View 26cc.
I think I have a new set of fiberglass profile gear somewhere if you are interested. I would send it your way for what the shipping cost.
David
I switched engines last week but haven't got to fly it yet. I had a DLE20 on it and switched to a Valley View 26cc.
I think I have a new set of fiberglass profile gear somewhere if you are interested. I would send it your way for what the shipping cost.
David
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ahicks (05-08-2021)
#31
Member
Thread Starter
David, thanks for the useful information, and wonderful offeron the gear legs. My zip code is 99353. Let me know what you need for shipping, and thanks again for the help.
Larry Fitch
Larry Fitch
#33
My Feedback: (2)
I learned about receiver "brown out" and did a lot of testing on a similar plane quite a while back. Since then, I run 2 switches on all of my single battery systems. This for redundancy (I've lost one too many planes due to faulty switches), AND to provide the potential for up to double the available amperage to my flight pack. Passing all of the flight pack power/amperage through one standard JR type connector is not something I would endorse for servos this size on a plane designed to fly like a MoJo can be flown.
I would also second Dave's thoughts on servo selection and setup. Too, on my planes, any 4-40 rod length of consequence gets run through carbon fiber tubing to keep it stiff. Something I started doing a long time ago.
Best of luck on the build! -Al
I would also second Dave's thoughts on servo selection and setup. Too, on my planes, any 4-40 rod length of consequence gets run through carbon fiber tubing to keep it stiff. Something I started doing a long time ago.
Best of luck on the build! -Al
#34
Member
Thread Starter
Al, Thanks for the good advice. I'll have to see how I can implement your recommendations into this build. The carbon tube over 4-40 steel rods is pretty standard on my builds as well. Not quite sure what to use for control rods yet, but being stiff is a requirement for sure. I doubt I will ever be flying the MoJoto it's limits. At 78 years, 3D is not in my normal routine--not for a long time, fingers are too slow.
Larry
Larry
#37
Member
Thread Starter
David, I'm not too concerned with weight. Relative to "spongy" do you mean "springy". My general concerns with aluminum is that they tend to bend, getting wider and lower with use. Does this glass unit spring out of shape, getting wider, or just springier meaning more difficult to keep plane on the ground during landing. Not quite sure what issue I'm looking at? The measurments look about right for the MoJo 65, so I'm interested, if usable. I have zero experience with glass gear. Thanks for the info, and offer
Larry
Larry
#38
My Feedback: (9)
Larry to better explain myself re: spongy. The gear will start to get more flexible as time goes on and start to sag. Sometimes one leg more that the other. It's never caused me any landing issues and it sort of cushions the landing. The opposite of a CF gear where the gear is so stiff it's almost brittle. I hope that makes sense. I still think I have another set around someplace and I'm looking for it.
David
David
#40
My Feedback: (2)
The thing I like about alum. is that they can be bent back into shape over and over again. I've never had an issue were they were straightened so many times they became weak or failed, but if I did, I'd just go up one size on the material dimensions I was using.
Too, the area of the fuse where the LG bolt holes are should be reinforced a bit to keep it from collapsing as the bolts are tightened - as well as from abuse (less than graceful landings). Soaking with thin CA works pretty good....
And for those that say you should learn how to land, landing something like this on it's tippy toes is pretty easy. It's the blown harriers (with 2' or less roll out) that are going to bend the gear..... -Al
Too, the area of the fuse where the LG bolt holes are should be reinforced a bit to keep it from collapsing as the bolts are tightened - as well as from abuse (less than graceful landings). Soaking with thin CA works pretty good....
And for those that say you should learn how to land, landing something like this on it's tippy toes is pretty easy. It's the blown harriers (with 2' or less roll out) that are going to bend the gear..... -Al
#41
Happy New Year everyone. I might be a bit late with this information but, Sig Manufacturing sells some good quality pre cut flat spring aluminium landing gear legs suitable for your size profile. You just need to bend, drill and cut to your desired size and shape....HTH.