There is a write up on the Internet on Bob's EAA webpage about his first flight and a little info. Here is the link
http://www.eaa23.org/pr-bob.htmBelow is the text of the web page. The pictures used to be on the webpage, but I couldn't get the pics to load up on the webpage this time. Don't know if its my computer or the pics have been moved.
Bob Clayton's - Thorp T-18
Thorp T-18 standard body plans #888 purchased in 1972, timidly began construction in 1973 and hope to be completed early summer 1999. Major items to complete at this date (24 Nov 1998) - cowling side doors, exhaust stack supports, canopy and windscreen and wing attachment and wing control hookup. Oh yes, and paint. Began construction on our living room floor and in 1976 moved into a new part time two car garage (mostly a hangar). Constructed with minimum basic shop tools (with a few of the small specialized aircraft tools necessary) and on saw horses (no specialized jigs). How is this done? Let me quote John Thorp from the early 60's.
"My system of building a metal airplane without jugs employs a system of locating the rivet holes in the detail parts through the use of transfer templates. With all of the holes in the parts, assembly is accomplished erector set fashion by clecoing parts into assemblies and then riveting. Aside from the obvious advantage of not being required to build jigs, this system has advantages of unusual component accuracy, convenient assembly sequence and simplified repair. "Matched hole" tooling has been used by various people in some degree for many years. Techniques vary between practitioners, but all are based upon the geometric theorem that "things equal to the same thing are equal to each other". If you have a set of holes in a flat sheet metal part and you want a number of additional parts identical to the first part you can use the first part as a tool and drill or punch the additional parts from the first part. Neglecting wear on the first part, all parts will be equal to each other. You can also transfer the hole pattern from the first part into a template and then use the template to locate the holes in the additional parts. The template pattern is identical to the first part and all additional parts have patterns identical to each other. If we use only reasonable accuracy in laying out a rivet pattern, and if we transfer the pattern exactly to its mating parts, the parts will go together and tolerance as such becomes of only academic interest. Airplanes are essential symmetrical. Parts on one side are frequently a mirror image of a corresponding part on the other side. If these parts have identical hole patterns and their mating parts have identical hole patterns the assemblies will be symmetrical and the airplane will fly straight. If we lay out a rivet pattern only once and make two parts at a time, we not only cut the labor virtually in half, but insure symmetry as well. Hole coordinating template techniques fit this scheme." It works! NOTE! The time I have spent working is not a reflection of John’s system of construction, but my inability to stay on task.
My engine - a 1950 stock Lyc 0290 D with about 85% new parts, assembled by Bob Despain at Precision Air in Salt Lake City. B&C starter and 40 amp alternator using a B&C LR-3 linear regulator. Exhaust system is a crossover system by Dean Cochrin with HPC High Performance Coatings inside and out. Piston skirts, valve springs, exhaust valves are also coated by HPC. The fuel system uses an Andair shutoff valve and gravity feed to the carb with a Skysports fuel probe for fuel quantity
I will turn a Sensenich W66LM72 wood prop. Full gyros with electric t&b, RST kit navcom, Narco transponder, RST kit intercom. Seats and upholstery by Ron Christensen.
I love my T-18!
Update! - First Flight 06/13/05 - Pilot, Danny Sorensen
The first flight of N818TR was conducted at approximately 09:30 on Monday, June 13, 2005, at Skypark Airport (BTF). Attendance was limited to a few family and friends. No public notice was made to the 'local flying community.
All preflight preparations completed. The passenger seat belts and shoulder harness were secured so as not to interfere with the flight controls. I strapped into the five-point harness and secured them tightly. All controls were checked to be within easy reach with the restraints secure.
Taxi to the active runway was completely normal as per prior taxi tests. Skypark uses a Unicom frequency of 123.00, and the call was made to taxi onto the active runway. One high-speed taxi was made, raising the tail off the runway to about 60MPH, then slowing down and returning to the taxiway. When the throttle was reduced the a/c felt very light. It was later confirmed with witnesses that the a/c had actually lifted off the runway slightly.
Engine gauges were monitored throughout this taxi period. Oil pressure and temperatures were within normal limits. The CHT was rising, but still in the green. It was felt that no further information was to be gained from additional taxi tests, so a takeoff was planned for the next run.
The radio call was made, and I back-taxied to take advantage of the full length of the 4700 foot runway. Acceleration proved normal. The engine RPM had been reaching only about 2000 on tests up to 60MPH. This was felt to be normal due to the high pitch of the propeller.
The a/c lifted off smoothly at about 65MPH IAS. I held the a/c level till the speed reached 8O MPH, then began a slow climb. Engine RPM rose to 2300, and IAS went up to I 100 MPH ROC was not observed at this time, although there is an ROC gauge in the a/c. The a/c felt very solid, with no signs of instability or out-of-trim condition, other than having to hold forward pressure on the control stick.
As per recommendations from other T- 18 pilots, the electric stabilator trim was set for a slight down pressure to aid in preventing overcontrolling in pitch on the first takeoff. After liftoff I was holding forward pressure on the stick to maintain level flight before climbing out. I trimmed the electric switch for down trim, and the pressure I had to hold forward increased, rather than decreased. Realizing that the trim switch was wired in reverse, I gave the switch full aft trim and was able to neutralize any stick pressure required.
First Flight Procedures
The objectives of the first flight were to establish a/c controlability, safe and normal engine operations, and any major or minor items that need correcting before any further flight testing.
The a/c climbed smoothly at I 1OOMPH IAS. Other than the aformentioned trim situation, nothing out of the ordinary was noted. A turn was made to crosswind, then very quickly to downwind, keeping a close pattern to facilitate returning to the runway should any emergencies arise.
The throttle was left in full-open position. On downwind the a/c accelerated to about 125-13OMPH IAS. Engine RPM read 2500. Oil temperature was at 180 degrees F, and the oil pressure at 60PSI, just within the green limits.
Three passes were made over the field at pattern altitude. The fourth and fifth passes were simulated approaches to landing. It was quickly discovered that the a/c is very slippery, that is, it was hard to slow down. On the sixth, and final, approach, the throttle was reduced at mid-field and the a/c was slowed to I 1OOMPH IAS by the time the turn to base leg was made. At this point the first notch of flaps was dropped. No additional flaps were used. The a/c was slowed to 90MPH IAS on base leg, then down to 85MPH on final, with engine RPM at about 1500. The approach was very smooth, with no tendency to divert direction or altitude. It actually felt like it were sliding down rails to the runway. Very stable, it flew much like a larger a/c.
Eighty-five MPH IAS was held to the numbers, then the throttle reduced to idle. The a/c flared very smoothly, with responsiveness, but not sensitivity, to stabilator input. With full-aft stick, the a/c touched down at the proper angle for all three wheels to contact the runway at the same time.
As the a/c rolled out straight and true, with only minor input to the rudder pedals, I made the audible comment to myself, "Well, that was a nonevent!", referring to the touchdown and rollout. I was rather surprised at how little effort it took to keep that a/c tracking straight.
No braking was used to slow down. I let the a/c roll till I had to add a little power to get to the turn off. I taxied back to the small gathering of observers, and parked in a tie-down spot before shutting down.
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