Q-talk 92 - VW Powered SuperQuickie
- Category: Q-Talk Articles
- Published: Thursday, 21 February 2013 11:53
- Written by Tom Solan
- Hits: 3895
by Tom Solan
Gene Knapp sent you some pictures of my Quickie. He said that you requested some written info including details of "How I did it" and "How it works", soooo, here goes-
The engine is a 1835 VW built from the Great Plains kit, with the compression ratio set at 6.94:1, no oil cooler, Zenith carburetor with homemade mixture control, Manley stainless steel valves, Revmaster oil pump, oil filter, and fuel pump assembly. It has pressure plenum cooling through aluminum chambers built with 6061-T6 .032 and .023 and no electrical system (although a 12 volt 2000 mah nicad battery pack powers a Facet boost (emergency) pump). The engine mount is a Great Plains X-casting bolted to 2 1.5"X1.5" maple motor mount bearers glued and glassed to the firewall. The bolt holes are 5/8" phenolic rod glued into the maple bearers, and reamed to 3/8" for the engine mount bolts. The prop is a Prop's Inc. 52 x 42 mahogany, which seems to be about right. The cowl is made from 2 plys carbon fiber and 2 plys S-glass layed up over a foam and plaster of paris mold.
Even though I built and installed the engine as light as I could, I still required 21.5 Ibs of ballast in the tail cone to achieve a balance point at the mid-point C.G .. Ofthe ballast weight, 7.5 Ibs is additional structure to support the added weight. A vertical lengthwise bulkhead (1" foam, 2 ply uni @ 45 degrees) now goes from FS 153 to the tail cone attach point. Top and bottom stringers were added from the turtledeck back to the mid-point of the tail cone, as well as vertical and diagonal stiffeners added to the interior fuselage sides. Stringers and stiffeners were made like the foam and glass engine mount stiffener listed in the Q-l plans. I also added 4 additional tail cone attach points (total of 12), increasing the thickness of the aluminum plates to .100" 7075-T6. The tail wheel's wheel pant was reinforced with 4 plys of S-glass and lead shotlflox was poured into the voids. The tail wheel pant now weighs 6.0 lbs.
|Additional Structure||7.5 lbs|
|Lead ballast tubes @ FS 153||8.0 lbs|
Aircraft empty weight 406.0 lbs.
The brakes are Hegar Posi-Stop hydraulic brakes bolted to Ken Brock lightweight aluminum wheels.
The tail spring is a stock Quickie fiberglass rod covered with 10 plys of S-glass bid laid up prior to gluing into the tail cone. Then 8.5 plys of S-2 uni were wrapped around protruding section (fibers lengthwise) followed by 5 plys ofSglass bid to blend into the tail cone. The tail wheel caster angle was changed to -1 degree which improved ground handling, especially in crosswinds.
Performance Specs so far - 30 hours engine time, 22.5 flight time:
|Static RPM = 2900|
|2750 RPM cruise||123MPH||
Fuel burn 2.5GPH
|2850 RPM cruise||128MPH||
|3200 RPM cruise||145MPH@8500'||
not computed yet
Speeds calculated by flying mUltiple triangular courses and averaging the GPS airspeeds.
|Rate of Climb at a takeoff weight of 625 Ibs.|
|OAT 48 F||@ 85 MPH IAS||
|OAT 75 F||@ 85 MPH IAS||
|OAT 78 F||@ 110 MPH IAS||
My conclusion is: "So far, so good." The airplane handles beautifully on the ground with the negative I-degree caster tail wheel. The hydraulic brakes are a vast improvement over the tire scrubbers. There is nice smooth deceleration after landing. Takeoff: WOW, what a nice feeling being pressed back into the seat while advancing the throttle. Climb: 1400 FPM on a cool morning! Need I say more? The cruise is silky smooth with the same beautiful in-flight handling characteristics you expect in a Quickie. This thing is an absolute BLAST to fly.