how to make a tow hook?
03-17-2009, 12:40 PM
#1
Senior Member
Thread Starter
My Feedback: (4)
Join Date: Nov 2004
Location: waterford,
CA
Posts: 104
Likes: 0
Received 0 Likes
on
0 Posts
how to make a tow hook?
Hey all i just finished my dynaflight bobcat. I want to launch it with a high start. I want to make my own tow hook and i want to know what everyone else uses to make and mount theirs. thanks.
03-17-2009, 02:31 PM
#2
My Feedback: (11)
RE: how to make a tow hook?
You can go to a hardware store and get either bolt hooks or screw hooks. They are pieces of metal with a 90-degree bend on one end and bolt or screw threads on the other. It's shaped like an "L" with the threads on the long end. You put a hardwood rail down the center of the fuselage that's supported by at least two bulkheads and screw the screw hook in at a point about 15-degrees ahead of the balance point.
If you use a sheet of ply for the bottom of the fuselage, then use a bolt hook with a small nut. You screw the nut on the hook then screw the hook into a blind nut you've installed in the plywood. You then use the small nut to cinch the hook to hold it in place.
This part also works:
GPMA1991 TOW HOOK SET SPIRIT 100 ARF US$2.99
If you use a sheet of ply for the bottom of the fuselage, then use a bolt hook with a small nut. You screw the nut on the hook then screw the hook into a blind nut you've installed in the plywood. You then use the small nut to cinch the hook to hold it in place.
This part also works:
GPMA1991 TOW HOOK SET SPIRIT 100 ARF US$2.99
03-17-2009, 10:44 PM
#4
Senior Member
My Feedback: (3)
Join Date: Sep 2002
Location: OZark,
MO
Posts: 2,694
Likes: 0
Received 0 Likes
on
0 Posts
RE: how to make a tow hook?
I just made up 2 for a pair of Gentle Ladys a friend and I are modding. I started with a 2" 10/28 bolt chucked the head into the drill press and used the dremmel to smooth of 1" off the threads from the head down. Then I heated it a little and bent the smooth part 90 degrees. cut the head off with the dremmel. Smoothed any spots that looked like they needed it. Do a trial fit it into the fuse so you can solder the inner nut. makes for easy tightening without getting into the fuse. We used the longer threaded section that sticks up into the fuse for securing ballast.
03-20-2009, 03:43 PM
#7
RE: how to make a tow hook?
Three are actually 3 in the final installation. That is so I can move the hook position to change the angle of the launch. This allows me to tune the launch of the plane as I tune the balance.
The more rearward would give me the steepest launch. But a rear hook position can make the plane somewhat unstable. This might a competiiton position.
The more forward would give me a flatter easier to handle launch. This might be a training posiiton.
So I can progress along the holes as I become more experienced and as I adjust the balance point of my plane. Typically I start them at the recommended balance point, then over time I move the CG back to get better thermaling resposne.
So much fun!
The more rearward would give me the steepest launch. But a rear hook position can make the plane somewhat unstable. This might a competiiton position.
The more forward would give me a flatter easier to handle launch. This might be a training posiiton.
So I can progress along the holes as I become more experienced and as I adjust the balance point of my plane. Typically I start them at the recommended balance point, then over time I move the CG back to get better thermaling resposne.
So much fun!
03-20-2009, 03:51 PM
#8
RE: how to make a tow hook?
When I started with my Spirit, the CG was as per plans and the hook would have been in the front slot. Today the CG is probably 3/4" rearward and I am probably in the back hook position.
Have not flown the Spirit in a while so I am not sure.
But, if I was going to teach a new pilot, would add a little weight to the nose, for stability and move the hook forward one hole.
Have not flown the Spirit in a while so I am not sure.
But, if I was going to teach a new pilot, would add a little weight to the nose, for stability and move the hook forward one hole.
03-31-2009, 08:31 AM
#11
Member
Join Date: Feb 2003
Location: Farmington,
CT
Posts: 86
Likes: 0
Received 0 Likes
on
0 Posts
RE: how to make a tow hook?
The simplest and best hook you can make with simple tools is made from a Hardware Store L-Hook. An L-Hook has a lag screw thread for a very strong hold in wood, and a #10 size ( approx 3/16" dia ) is strong enough 2-3 Meter size. Using a couple of pcs. of scrapwood clamp the L hook in a vise and with a Hammer pound it over to a 90 deg. angle. You only want from 3/16"- 1/4" between the end of the thread and the bent pc. (this keeps tow point from moving around from a level throw to the transition into climb mode) .
Buy a several L hooks as you really only get one chance at bending it . With a hacksaw ,cutoff wheel, or whatever you have cut the bent part to about 1/2" long from the inside of the bend. Grind or file the end of the hook so It's smooth and rounded . Epoxy a pc. of 1/4" ( or 2pcs. of 1/8" ) plywood into the fuse . Drill a hole the same diameter as root size of the lag thread into the fuse and plywood ( I locate my towhooks just fwd of the CG) . Screw the towhook into the fuse just until the thread disappears into the fuse. Lock the towhook in position with a drop of thin C/A . I use the same style hooks from 2M floaters to 3M moldies
Jim B
Buy a several L hooks as you really only get one chance at bending it . With a hacksaw ,cutoff wheel, or whatever you have cut the bent part to about 1/2" long from the inside of the bend. Grind or file the end of the hook so It's smooth and rounded . Epoxy a pc. of 1/4" ( or 2pcs. of 1/8" ) plywood into the fuse . Drill a hole the same diameter as root size of the lag thread into the fuse and plywood ( I locate my towhooks just fwd of the CG) . Screw the towhook into the fuse just until the thread disappears into the fuse. Lock the towhook in position with a drop of thin C/A . I use the same style hooks from 2M floaters to 3M moldies
Jim B
