Fightercat Cheetah - Red Bull Twin - Page 6 - RC Groups
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May 24, 2012, 11:22 AM
Redneck Injuneer
bill34207's Avatar
Guess it's time for another little update on this one. I haven't really done anything noteworthy myself but did go over and visit with Dave of HRC Mfg for a little while this morning. Scott (tiqueman) took my mount template and drew it in CAD to make it easier for coding into the CNC machine and got an email from Dave this morning saying he was going to cut a basswood trial run on the program.

Since I'm taking a couple of vacation days to make a long Memorial Day weekend, I went over to watch the process and shot video of it. It was about a 30 minute run on the mill but edited the video down to just over 7 minutes. Something I thought might be interesting for some of us.

HRC CNC Mount for Fightercat Cheetah.wmv (7 min 30 sec)
Latest blog entry: Freewing A-4E/F Skyhawk 80 mm
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May 24, 2012, 06:28 PM
Registered User
osprey21's Avatar
Nice work Dave. I should have listened to my grandpa and become a machinist.
May 25, 2012, 12:32 PM
Redneck Injuneer
bill34207's Avatar
I finished doing a motor transplant in my Sprintcat last night in hopes of getting better run times than with the 1717. (finally putting the 1527 I bought from you to use scorp)

After that started on the steering servo mount for this one and finished it up a couple of hours ago. Got a call from Dave a little while ago too and just have got back from his house. Sure is nice living within a couple miles of him.
Last edited by bill34207; May 25, 2012 at 10:10 PM. Reason: added photos
May 25, 2012, 08:46 PM
retired ATC
ron1950's Avatar
looks good bill.....i with you...i cant get the energy to prep my boats for some reason.....
May 25, 2012, 10:55 PM
I feel the need for speed!
scorpion1's Avatar
Looks great..................why do the mounts look "grubby"?
May 26, 2012, 06:25 AM
Redneck Injuneer
bill34207's Avatar
The "grubby" look is functional and caused by roughing up the surfaces to help insure good adhesion to the cloth & resin. I suppose one could go back and polish them up a bit but I'm not that much about "bling" and they don't show after the hatch is on.
Latest blog entry: Freewing A-4E/F Skyhawk 80 mm
May 26, 2012, 02:22 PM
Registered User
Quote:
Originally Posted by osprey21
Nice work Dave. I should have listened to my grandpa and become a machinist.
Thanks Chris. Being a (want a be - machinest dose have its moments.
May 26, 2012, 02:32 PM
Registered User
Quote:
Originally Posted by bill34207
The "grubby" look is functional and caused by roughing up the surfaces to help insure good adhesion to the cloth & resin. I suppose one could go back and polish them up a bit but I'm not that much about "bling" and they don't show after the hatch is on.
Bill, do the mounts feel good and solid after being mounted? Checking how it worked out without holes for the adhesion to flow through.
May 26, 2012, 04:16 PM
Redneck Injuneer
bill34207's Avatar
Quote:
Originally Posted by HRCMFG
Bill, do the mounts feel good and solid after being mounted? Checking how it worked out without holes for the adhesion to flow through.
Hi Dave. There's have a little flex if you lean on them hard enough but it's flexing the whole hull and not the mounts. I did 3 layers of 2 oz. cloth on one side, then filled any gaps with epoxy & milled glass from the other side before adding another 3 layers of 2 oz cloth to it. They are in there pretty solid.

Edit: To avoid being totally lazy while waiting on a few more odds n ends to arrive (getting bored with a long weekend off) went ahead and added the bullets to the motor leads and esc so they will be done.
Also ground a flat on the motor shafts since these do not have one from the factory. (They're designed for a pinch collet in EDF applications instead of a set screw) Mostly shot a photo of this to leave a handy tip for anyone that doesn't already know. You really don't want to let metal filings get into your armature and an easy way to prevent it is to seal the openings of the motor while grinding. A piece of wide masking tape works pretty well for me.
Last edited by bill34207; May 28, 2012 at 08:57 PM. Reason: edit
May 29, 2012, 08:55 PM
Redneck Injuneer
bill34207's Avatar
Kinda hate to bump this before some more actual work is done but looking for an opinion or two. My Kintec order showed up today with the bearing spacers so bolted a motor back in and made up a stuffing tube. Does it look like too much of a bend?

I'm not going to install them until after I get the motor motor jackets anyways so wouldn't mind a little input in the meantime.
Latest blog entry: Freewing A-4E/F Skyhawk 80 mm
May 29, 2012, 11:37 PM
I feel the need for speed!
scorpion1's Avatar
I really dont like that bend Bill.......................too severe and sharp.
May 30, 2012, 08:32 AM
Registered User
Pseudonym's Avatar
Can you give thr bend a bit more radius?
Try putting the flex in where its going to be. A lot depends on whether the flex freely bends at that point, or if its a little stiff from the solder joint.
May 30, 2012, 12:11 PM
Registered User
stiks's Avatar
Bill,..on your stuffing tube...do you have it soldered at the end...you know..one tube inside the other..then soldered?....not to take away from this build but is that what i should do with my 50"? since i have a tube within a tube within a tube?

Great build so far....!!
May 30, 2012, 06:41 PM
Redneck Injuneer
bill34207's Avatar
Quote:
Originally Posted by scorpion1
I really dont like that bend Bill.......................too severe and sharp.
I wasn't real happy with it's look either. I mostly wanted somebody else to tell me it was too sharp. I'll make another attempt in a bit. Running a little late getting home this evening after stopping by Dave's on the way home. I have cooling jackets now.

Quote:
Originally Posted by Pseudonym
Can you give thr bend a bit more radius?
Try putting the flex in where its going to be. A lot depends on whether the flex freely bends at that point, or if its a little stiff from the solder joint.
I'm going to remake one after while and see if I can stretch the radius out a little more and still get the alignment right on the motor. The solder joint for the stub shaft is nowhere near close to the bend but it's still more of an angle than I'm comfortable with.

Quote:
Originally Posted by stiks
Bill,..on your stuffing tube...do you have it soldered at the end...you know..one tube inside the other..then soldered?....not to take away from this build but is that what i should do with my 50"? since i have a tube within a tube within a tube?
It is soldered where it steps down to the tube for the motor end. I have used loctite 603 to do the same job but just went ahead and soldered this one since my torch and solder were laying handy.
If you decide to do it, keep in mind that there is only about 1/4 to maybe 3/8" of the smaller tube inside the larger one. I just add them to help keep down water intrusion up the flex since I'm not running a liner.
Latest blog entry: Freewing A-4E/F Skyhawk 80 mm
May 30, 2012, 08:05 PM
Redneck Injuneer
bill34207's Avatar
Just made another tube and it's an improvement. About as good as I'll be able to get with the short working length. It looks more acceptable and has a better feel to it when spinning the cable inside.
Latest blog entry: Freewing A-4E/F Skyhawk 80 mm


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