Radio static solutions for Case mags & unshielded ignition?

[Joel Severinghaus]

Several of the potential buyers for my Taylorcraft have expressed concern about radio static with the unshielded ignition. Doesn't bother me, but I want to reply with progressive suggested solutions. I've used the Search function to look at the various radio noise and ignition shielding threads here, which have helpful, specific advice.

Tell me if this looks like the correct order of fixes for the next owner to attempt, from cheapest and easiest to more expensive:

1. Wires to ignition switch are already shielded wire.

2. Install a magneto noise filter? (But will that work with Case rather than Bendix mags?)

http://www.aircraftspruce.com/catalog/elpages/lsMagFilter.php

3. Install a braided ground strap to ground the engine case to the engine mount?

4. Replace the Sporty's SP-200 handheld radio with an Icom IC-A6 or IC-A24, which have an "automatic noise limiter"? ($279 or $309)

5. Put shielded ignition harness on the lower plugs only? If it's even possible to fit shielded wires into the Case distributor cap? ($150?)

6. Replace the Case mags and harness with a Slick upgrade kit and Ercoupe cups for the top plugs? ($2000?)

Thanks for your help!

[Pearson]

Re: Radio static solutions for Case mags & unshielded ignition?

Joel,

What about option #7; Find buyer who appreciates authenticity of a quality restoration.

[Joel Severinghaus]

Re: Radio static solutions for Case mags & unshielded ignition?

Well yes, that goes without saying, and would be my first choice. I've been talking with several potential buyers who would gladly take her as is, and aren't worried about radio issues. I don't want to sell her to someone who would put bumps on the cowling for shielded top plugs.

[robbie]

Re: Radio static solutions for Case mags & unshielded ignition?

Joel

Here's my two cents worth.
I had two case mag before installing Bendix's mags.
I think the case mags had less noise than the Bendix's.
Maybe they had weaker spark??
The mag filter isn't going to help much.
Can't put shielded wires on the case's.
Icom radio with anl does help, but still get it.
I do know what one guy did.
When to the auto part store,got 15ft of resistance plug wire,put the ends on them, and flew it for 5 years like that. It really quited the radio.
Legal no.
But the way Joel, I found my Bendix's mags used for $600. with 100 hours since overhaul. $150. for the harness.$750.

[3Dreaming]

Re: Radio static solutions for Case mags & unshielded ignition?

Well yes, that goes without saying, and would be my first choice. I've been talking with several potential buyers who would gladly take her as is, and aren't worried about radio issues. I don't want to sell her to someone who would put bumps on the cowling for shielded top plugs.

Joel, having had an award winnig T-Craft I know what you mean about changes to the airplane but the right buyer is the one who has cash in hand. If the buyer is willing to give you enough money that you will sell the airplane you should sell it. After you sign the papers you have no control over what is done to it. You may not be happy, you might have regrets, but you have your money. When I had my BL there was a guy who wnated to buy it to use it for an experimental engine test bed. If he had come up with the money the airplane would have been gone in a heartbeat. Tom

[Hank Jarrett]

Re: Radio static solutions for Case mags & unshielded ignition?

You can also make cans for the plugs or use Ercoupe cups for the hot end of the plug wires. Make a metal can to cover the back side of the mag switch and ground it to the airframe. The inside has to be insulated so it can't short out the switch. The ends of the "P"Leads can radiate some noise.
Hank

We are really digging here but at least these don't require permanent changes to the plane!

[jim cooper]

Re: Radio static solutions for Case mags & unshielded ignition?

I have an Icom with a direct connection to antenna mounted on top of cockpit. With the AN turned on the static is not too bad and I trans. and receive quite well. While this may not be original, I'm much more interested in being heard in a pattern as this is where many accidents occur. My last T Craft was involved in a pattern fatal in 1977.( no radio) T-Craft made it to the ground, other pilot in cub was killed. At this point originality seems unimportant.JC

[Buell Powell]

Re: Radio static solutions for Case mags & unshielded ignition?

Joel,
I read in another post that you installed an advanced aircraft antenna. I installed one in mine about 1/2 way from the cabin to tail-as far as practical away from the engine--It made quiet a difference in the noise and a LOT of difference in reception. Not sure if it will help but just moving it back may may help.

[RoN43220]

Re: Radio static solutions for Case mags & unshielded ignition?

When I got my Tcraft it had an antenna above one wing root. Lots of noise. I bought a fancy one that looked like the letter E and put it in the fuse. Mediocre reception and didn't look good on the SWR meter - likely because of the steel tubing.

Then I noticed a plate covering a hole under my seat in the center where it's metal and makes a good ground plane. Around a foot or so aft of the bungies. I put the original antenna which was wire with a slight bend in it in that spot and it worked very well. Especially after putting shielded plugs and wire on the bottom four. Since you want vertical polarization I thought an even straighter antenna would work better altho' it could touch the ground. So I switched it to an ELT antenna because it's black, you barely notice it and it's flexible. It's worked so well that I haven't bothered to do anything with the top 4 other than putting metal braid over the wires.

Ron

[Joel Severinghaus]

Re: Radio static solutions for Case mags & unshielded ignition?

Thanks for all the suggestions, guys. I know I can always rely on the tribe for technical expertise. I'm sure going to miss that when my Taylorcraft is sold.

The radio concerns were coming from potential buyers who fly near/under/in controlled airspace. I have a deposit in hand from a committed buyer who may come get the airplane this weekend, and he may not have issues with the radio static where he flies, but I'll pass all your suggestions along to him in case he wants to try something in the future.

Bob Gehring in Wisconsin is the only other pilot I've met who still uses Case mags, in both his Taylorcraft and his Cub. His solution to EMI from the ignition leads was to keep them all about an inch apart with friction tape spacers. (Photos below.)

Robbie: Yeah, if only it were a simple matter of automotive spark plug wires! I suspect the next owner, if he does replace the mags, would probably just go with new Slicks rather than used Bendixes.

Tom: You're right, of course. When she's gone, she's gone. But one can always hope that one's beautiful child doesn't go out and get piercings and tattoos...

Hank: My mag switch already has what looks like an original metal can covering the back side, but I don't recall that the can itself is grounded to the airframe. Good suggestion.

Buell: I do like my Advanced Aricraft internal antenna, and I think it works better than the previous whip antenna that protruded between the bungee covers. It might be a simple matter to move it a few feet further aft in the fuselage.

Ron: Sliding metal braid over the existing ignition leads is an intriguing idea. Can you suggest a source or part number?

Thanks again, everybody.

[RoN43220]

Re: Radio static solutions for Case mags & unshielded ignition?

Sure, it's Aircraft Spruce part# 11-02463 but try this link: http://www.aircraftspruce.com/search...braid&search=1

It doesn't need to touch metal at either end if it gets grounded somewhere in the line. I just took the grommets off the holes in that metal plate between cylinders to it gets contact there. Looks good too.

Ron

[robbie]

Re: Radio static solutions for Case mags & unshielded ignition?

Ron

Is the $0.70, per foot or what?

Thanks

[RoN43220]

Re: Radio static solutions for Case mags & unshielded ignition?

Yes, you buy it by the foot. And if you want the ends really nice looking then buy the heat shrink. When it arrives it's flat so it helps to push something thru' it to round it out and open it up - a long dowel that's been pointed on the end works very well. Easy to work with, it will open up to about a half inch, and worth doing.

Ron

[Joel Severinghaus]

Re: Radio static solutions for Case mags & unshielded ignition?

Heck, Robbie, for only $0.70 per foot from Aircraft Spruce, you don't have to sneak off to the auto parts store!

[robbie]

Re: Radio static solutions for Case mags & unshielded ignition?

You'r right Joel,will oder some this week, will make a nice winter night project.