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rudder travel stops on 9 or 7

A

alpinelakespilot2000

Well Known Member
For some reason on the 9 plans, the instructions don't have you fabricate and install the rudder travel stops until the VS and rudder is fitted. However, is there any reason not to drill and attach them now before the tailcone gets riveted together? It would seem that would solve two issues:
1. Rather than using CS-4s for the forward rivets to hold stop on the tailcone I could use solid 426's; and,
2. More importantly, it would allow me to debur those #30 holes that I'll be drilling through the tailcone skins and stringer.
Any problems with doing it now?
 
I'd wait... first, the shape of the stops as called out on the plans aren't exactly right. I had to make a second set. Also, you'll want to make sure they are positioned so that your rudder won't hit your elevator and you don't even want it close as I've heard that a wind gust catching a rudder will flex it enough to hit the elevator.

Check this out as an option:

http://www.jeffsrv-7a.com/FUSELAGE/04-07-22.htm
Plans: http://www.jeffsrv-7a.com/RudderStop.htm
 
1 Reason

I made mine according to the plans and they were to small. the rudder swung to far.--Make em again :confused:
Frank
painting
 
Rene Bubberman said:
We made Delrin rudder stops based on Jeff's, see: http://websites.expercraft.com/PHVII/index.php?q=log_entry&log_id=3249 and beyond.
If you need cad-drawings (pdf/dwg/dxf) please let me know.
Click to expand...

Thanks Rene--It would be nice to be able to do away with the alum. angle stops altogether, and I've seen someone else do the same for the aileron stops, but one question I've had is whether or not the delrin will wear over time and eventually allow more travel than it should. Also, is delrin strong enough to not have to worry about it cracking at the bolt and then falling off the hinge bracket altogether. Probably a dumb question for anyone who knows anything about delrin, but I'm not one of them.
 
I would like to have a dxf or dwg of the Delrin part if it's not too much trouble.
I wonder if the travel stop is the same on a 7 and 9.
jim at aero-mold.com

Thanks
 
Steve, WAIT, Wait, wait! Your reasons are THEORETICALLY sound, BUT wait until you fit the vertical fin and rudder. As others said, the stops are too "short" allowing too much rudder travel, i.e., bumped into the elevator. :eek: :(

I had to "add" 3/16 to 1/4 to the rear edge that bumps into the rudder horn -- that's after the third set (translate: several hours of mfg. cutting, fitting!). After looking at the plans and lining the stops with the fusleage skin, I also was not happy with location my modified "factory" stops contacted the rudder horn. They were about 3/16" high, that is, above the bottom edge of the rudder horn and well into the web of the horn. It seemed it should contact lower, where the horizontal part of the horn angle is strongest. I ended up adjusting the stop to contact the rudder horn with about 1/16" of the rudder horn below the stop and drilled the rest of the holes in the stop, pop riveted it on (per plans) - and walked away.

Does that make sense? Anyhow, the rudder stop now contacts the horn where there is a lot of "meat". I feel better about that.

If it isn't too late, make the rudder stops according to the plans EXCEPT the cut off angle -- just don't cut it off until you have the rudder in place and you can scribe the stop to the rudder horn v-e-r-y carefully because it swings at an angle to the stop.

Don Gray
Cortland, OH
7A N17QB in progress
 
Terry,

I'm pretty sure that those white plastic cutting boards are made from Delrin. You need one of the thicker ones, but I have seen them for $6-$10. I checked several places on the web (one was www.professionalplastics.com) and they want about $45 per square foot for a 1/2" sheet, with the smallest sheet being 12" x 24". Some Ebay sellers are asking $14 for a 5" x 5" x 1" sheet. I think I'll just use the cutting board.

Tracy.
 
Just to add something new into the mix, you might also look at PCB board material. It's the stuff that's usually brownish in color and is a highly compressed mixture of fiber and resin, and can be gotten in thicknesses up to around 1/2" or thicker.
It's so tough, it will pretty much destroy any say blade used on it.

It could be an option at least worth looking at...
 
Phenolic (SP) material, should be able to get that easily. Lots of aviation uses similar to this.

Jekyll
 
Delrin source

TerryPancake said:
Where is a good source for Delrin?
Thank you.
Click to expand...
I got mine from McMaster Carr - look under non-metalics, I don't remember if they call it Delrin or not, but it is the same stuff.

Dennis Glaeser
 
Aircraft Spruce sells nylon sheet that is a very good substitute for delrin. It is priced by the square foot but comes in 6" X 6". Just order quantity .25 sq.ft.
This is what I used for control column bearings on my bi-plane.
Mel...DAR
 
Mel,

Got any pics of the biplane project? If I ever get the energy together to build another plane (unlikely) I'd love to do an open cockpit biplane.
 
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