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I’m going to modify one of my F1H’s into a circle tow.
It’s strong enough.
It won’t be a bunter. Seems I never put more than 2-3 lbs on it for a straight tow.
What force do fliers set the latch to release at for these smaller planes?
Try starting with 2.5 kg unlatch tension.
It will help if you have a spring balance of suitable range to measure this.
Be prepared to make changes to the tension to suit things such as
– how the model likes to fly
– how you like to fly
– calm or windy
– what the model does when you get it up to the required speed and tension to unlatch, ( this may be unknown territory for you and the model).What sort of hook do you have ?
A critical part of setting up the hook is the timer start, or rather the stop. You definitely dont want the timer running down while towing.
Circle towing is a lot of fun, F1H models move quickly, so you will get plenty of that. Good luck.
cheers
David Ackery
Thanks Dave,
The hook I have unlatches at a little less than 1.5kg.
I’ll make another one, stiffer.
This is a good thing as it was really just a prototype to see if it would do everything. It doesn’t and I can make it better at the same time instead of hacking up the original.
I finished the towhook.
Found a great hardware store with a nice assortment of springs.
I can unlatch in a range from 6-9lb of tension.
A stop for limiting/adjusting both tow and glide circles.
Attachment points for timer start and rudder line.
A zoom rudder that only goes into effect once the hook has been unlatched.I wish I had that last provision on the hook for my F1A. I’m still trying to figure how to add that to the Czech hook that’s in it. 😕
The one on the left is the original model, should be nice for a Classic towliner.
Slowly, it seems, I worked and ended up putting the hook in a”YeahBut”.
I had to build one of the latest versions with two piece wing anyway.First towed test flights today!
Glide was nice as it was set previously in a spat of good weather.
Hook release at 6.25 lb
Stiff wing! No flutter. Really stiff!!!
Zoom rudder worked well.
Incidence/CG needs to be reset for better gain in the zoom![had to much incidence]Unlatched itself in the 8mph winds.
Increased unlatch force to 8.5 lb.I just finished the latest, revised YeahBut.
Lower profile pod, nose length increased slightly.
Shorter tail boom.
Tip panels longer, mains shorter, span increased by 1″..JPG)
I have been thinking about building a smaller glider and this looks like a nice one — do you have plans? I am impressed by your home made circle towhooks. I built one once based on a schematic in Bob Stalick’s Model Builder column. It didn’t work out, although it was probably more my fault than the hook design. I’ve went back to straight tow which is what I’ve been flying ever since. The new classic towline event has been a Godsend. However, I do have a nice circle tow hook for a small glider that I got of e-bay, so I might be tempted to give it another shot.
Thanks,
SimonThe YeahBut design, as a circle tow plane, has done very well and I still fly it. The straight tow version, of which a few have been built, has also done well in the hands of others.
The one in the last picture had a lot of promise but I lost it while test flying! I don’t use a radio so it was gone. I had just finished another one at the Nat’s. I used a purchased F1h hook in it and couldn’t get the hook positioned correctly, the spar location hinders it’s placement. When I get some time to reposition the spar in the parts and get another one cut I can trim one out.
I used the black nosed one iat the Nat’s and did well but I have to say, I wasn’t really trying hard and kicked myself later for making some of the decisions I made that day.
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