Thorp Air Command - T18.net

You will get a multitude of advice on this subject ! You can remove the flap handle (does away with the trim knob) and go with electric flaps. You can remove the center tunnel and put the rudder cables outboard. You can remove the standard center tunnel and put in a "rounded" tunnel. The S-18 is "2" inches wider. Wider than a C-150/172 ( I think ?) Take off your winter coats and wear short pants !

RB

You're right Rich. Roy Farris did a write-up, but I couldn't find it. Every time I downloaded a NL found using "Aft Tunnel" for the search, I was unable to return to T18.net. I could only find my paper NL's to #123.

Basically, he took the old tunnel and cut off the sides. Then split a piece of aluminum tubing and riveted the sides to it.

I've always thought about using a smaller diameter tube with a bellcrank in the middle (Like the EAA Biplane). I think it would lower the angle so the tunnel could be narrower and lower. I have a EAA Biplane elevator tube assembly to play with to see how it would fit. Maybe next spring.

Bob MO

Bob please explain the download troubles (you can send me a private message)

The two biggest bang for your buck and least invasive changes regarding hip room are installing electric flaps (see the next NL I'm doing an article on retrofitting an existing aircraft with electric trim/flaps) and a rounded tunnel. Both are relatively simple to do and the the rounded tunnel alone buys you another couple of inches.

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

Make sure the "rounded tunnel" is beefed up enough to stand on. Otherwise you will be in the same miserable boat as the RV guys and will have to stand on your seats to get in and out of the plane.

The center pivot elevator tube is an option, however, such things as resonent frequency and weight are a factor. I had the Thorp designed (plans spec) push/pull tube analized by a NASA engineer and he said leave it alone.

_________________
Bob Highley
N711SH
SN 835
KLAL

Marilyn and I checked out an S-18. I don't want to identify it yet because I've not decided what to do about it.
The guy that built it has passed, his widow and son are selling it. The S-18 fit well, but this ship has a prebuy inspection with an estimate for repair that was about $11,000.
After a month of so I made an offer that was rejected as too low, but factoring in current selling prices for aircraft, the work & expense I would have to put in, and the risk of the unknown, I had to temper my offer.
Meanwhile, I have found a few more Thorps for sale, some right here in the Puget Sound area.
I'm trying to contact Ed Ullrich, who has advertized his ship with EAA 26 chapter. It's N883FF.
Does anyone know him or anything about it?

I couldn't get ahold of Ed, so Marilyn & I went to the airport, where the old airport bums remembered him. The manager was nice, and said the plane had always been hangared, but had been moved. She wouldn't say where, and said she couldn't show us the plane without permission. That's to be expected.
But she did call the owner's daughter, and forwarded my phone number and message.
I got a call from her last night.
Ed had a stroke in 2004. He and 883FF have not flown since. Ed is still alive, in assisted living.
I'm trying to contact the guy who has the hangar, so we can see 883FF. Chris the daughter lives out of state. I think she understands enough to process the sale if things work out.
I guess we'll find out soon!

We bit the bullet and bought N883FF:

Congrats on the purchase, hope you have many hors of fun in your new Bird!!! Dan

Ditto what Dan said ! Fill it up with go juice and have fun !

RB

Scott,
That bird will make a great addition to the Thorp squadron in Chapter 326. Need details when you get a chance.

_________________
Bruce Finney
N18JF T-18C #262
Yelm, WA USA

We spent a few hours with it this evening.
The 9 year old mogas was drained using the electric boost pump, and put in my 1989 Chevy PU, which was on Empty. That 20+ gallons of gas ran my 4.3 V6 ok on the flat, but pinged going up hill. Smelled bad too.
The gas tank has rust from the fuel level sender and grease blobs from the cap in the bottom, but the finger strainer is still visually clean. The tank is pretty stout, with welded top & bottom bungs.
The fuel valve is direct mounted to the tank, and was stuck in the closed position. Took some careful persuation to get it open. My first experience 'diving under the dash'.
The engine is an O-290G converted with an O-320 crank. It has mechanical tappets. The oil is clean & clear on the stick, and also when sampled from the drain.
The engine compartment is very clean and orderly, with fire sleeve on the hoses etc.
It has an O-320-E sump and carb.
Ted Hendrickson Prop. It has some hangar rash on the trailing edge. maybe a hot trouble light was too close and left a mark on the fiberglass wrap?
Aircraft built by Fred Ferguson, with an empty weight of 919#.
Total time Aiframe & engine 267 hrs.
The battery is in the back, a Gil G-35. It had an 11.5 Volt charge, so I put the charger on it and started testing the electrical system. It has an external power receptical.
Tomorrow I mop the gas tank. Then pull the plugs, inspect the cylinders and fill each with Marvel Mystery oil while on TDC. It's my way of making sure the rings are lubed all the way around. Makes for a smokey first start tho-.

I really like that shade of blue. Looks sharp. Congrats

By the way, once you get her flying, I would be interested to hear your comparisons between your RV-8 and the new Thorp.

Im curious what those that have actual RV stick time have to say about flying a Thorp.

Nice looking airplane! Congratulations.

MoGas is fine if you're flying a lot, but it doesn't like to sit. It can get gummy over time. You may want to take the carb off and check it over carefully.

And yeah.. it sure does stink.

The SAGA continues.
I don't know where to post now, I'm in that limbo, was looking for a Thorp T-18 or S-18, now I have one, but still it seems like a dream.
Each day in the hangar is a thrill. 883FF was a dusty blue promise. Now it's been washed, polished, and brakes bled. The controls inspected and lubed. The fuel tank drained and mopped out. Added 5 gallon 100LL.
Pulled the top plugs and filled each Cylinder @ TDC with Marvell Mystery oil, then hand pulled the prop 20 or 30 turns for feel. Then ran the starter, plugs still out, until generous oil pressure. Then plugs in and Start It Up!! THE MOMENT to LIVE for. CHUFFING and Barking, with Marvel oil smoke, it came to life, and settled in to a nice steady beat. Solid tappets tickling, unmuffled crossover pipes gently barking, and that great propeller wind!
A few minutes later, shut down. Engine seems good, but much inspection remains. Jump starting from the truck is a drag, so we got a NAPA 7581R and some post adapters. That equals the 28# weight and cranking power of the Concorde RG35, at $110 savings. Starts good too.
Taxi tests went well, including a full power run up, and Marilyn did well with it. She needs more seat cushions. I need less.
The tail wheel is a question. It's a Maule wheel? one arm on the right side, with a leaf spring pack?
The solid rubber tire is worn more on the right side. Looks funny, kind of a taper...
Ron Wantaja the aviation author is hangared right across from us. What a kick.

Scott,
That's a good looking Thorp! Well done!

As far as the tail wheel goes, over the past several years there has been a trend for people to go to the rod spring tailgear. I personally do not see a notable difference between the leaf spring and the rod. In my opinion the rods biggest benefit is aesthetics and drag reduction. With that being said I would not feel a dire need to change out the spring, thorps flew for 40 years with the stock spring. As far as the actual tail wheel goes the maule is notorious for the "lean", if the tire is well worn and aged you should probably consider replacing the maule with an ACS or Lang tail wheel. When the maule throws a chunk of that tire off, you

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD