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High Flight Articles

Volume XI No. 1 Page 25 1990



ED MAHLER PJ 295
By Chuck Spencer 821

v11-1-25a.jpg - 7.9 K

Ever hear of Big Ed Mahler? Maybe if I say Ed Mahler and the P J 295 many years ago but for the life of me I can't remember where. However, I was impressed with the performance of the PJ 295. A while ago I received a copy of a set of plans for the PJ 295 from John Tanzer. John is practically a charter member of the I.M.A.A. having number 35. John also was taken by the performance of the PJ 295 and has drawn plans in quarter scale. John got a set of three views of the airplane from the designer Nick DeApuzzo and proceeded from there. He has come up with a very excellent set of plans. The wing span is 81 " with an area of 1,836 square inches and a weight of 20 pounds, giving a wing loading of just slightly over 25 ounces per square foot. John powers his airplane with a Saito 270 and says the vertical performance is very good. However, a friend of his tucked a G 62 in his and says the performance is awesome. I certainly hope he used functional flying, landing and tail brace wires.

The plane is on three sheets. The first sheet has a left view of the fuselage and fin and rudder. The fuse is constructed from quarter inch square longerons, uprights and diagonals of spruce, with the forward end from firewall to the rear of the cockpit lined with a thirty second ply doubler, then three thirty second formers and all stringers are added. Landing gear is from one sixteenth aluminum with five inch CB wheels and wheel pants. The windshield and canopy are from a cut down Byron Pitts canopy.

v11-1-25b.jpg - 8.4 K

The firewall is from quarter inch ply with a standoff mount for the engine. The spinner is a four inch CB. Cabane struts are from K & S streamline tubing. The fin and rudder are from an eighth balsa core with lightening holes and ribs added to both sides. A CB tail wheel unit is used and the position of the tail brace wires is shown. The landing gear and tail wheel are mounted to quarter inch ply plates and the fuse is sheeted outside from firewall to front of the cockpit with eighth balsa sheet. The engine has one degree right and down thrust and the wings are mounted at zero degrees incidence. The stab is one and a half degrees positive incidence. A floor in the cockpit is from eighth lite ply

The second sheet contains full length drawings of both wings which in itself is a big plus with me. Both wings have quarter inch square spruce spars for both the front and rear. There is shear webbing running the full length of both spars forming an "I" beam which is light and strong. All ribs are from three thirty second balsa sheet with ply ribs at stress and load areas. Both leading and trailing edges are sheeted with three thirty second inch sheet from the leading and trailing edges back to the spars ... so in effect you have a "D" tube section on both the leading and trailing edges.

John mounts the aileron servos out in the wings. All four ailerons have the bottom leading edges beveled and hinged at the top with large quarter scale hinges. In my opinion, this airplane lends itself very well to the friese type aileron with torque rod actuation from the center section of the bottom wing. I've been using this method for about 3 years now and it makes for much more effective ailerons and I have yet to experience any flutter because the pivot point is moved rearward and centered vertically in the aileron so that when it is deflected up the leading edge protrudes beneath the wing and the air stream passes over and around it smoothly taking some load off the servo. This helps prevent adverse yaw. On the top of the up deflected aileron you have a smooth surface and about a one sixty fourth gap presenting a smooth surface to the air stream. You may not agree with me, but go to the airport and check out just about any airplane. Both the upper and lower wing have 5/16 the dihedral. All four tips are from eighth lite ply sheet with lightening holes.

Sheet three contains all fuselage former templates plus a front view of the fuse with landing gear shape and cabane strut mounting with brace wire mounting. I particularly like the method of bracing the cabane wires. It's simple, easy and functional, plus it can be adjusted. Also shown is the method of strengthening the K 8c S streamlined tubing used for the cabanes. Also on this sheet is shown the stab and elevator construction which is the same as the fin and rudder. I don't know if any of you have tried the DE hinges yet, but if you haven't you should. I use them almost exclusively on empennage control. I was dubious at first because they only butt mount with CA, but after five years I've never had one come loose, and the control surface can be deflected 90 degrees and separated from the stationary part making it much easier to cover, and there is no slop, repeat NO SLOP. They must be sanded to remove the mold release before gluing, and where they are to be covered I used Balsarite. Also on control surfaces where I can, I use the G&C gapless hinge which snaps apart. I like these very much also.

So if you want a very aerobatic bipe, different from the usual Pitts, Eagles, and Weeks, get yourself some See Temp, another good product, a set of P J 295 plans and have at it. You won't be sorry. Order the plans from John Tanzer, 166 North Lehigh Avenue, Cranford, New Jersey 07016, at $35.00 a set rolled in a tube. Cowl and wheel spats can be ordered from FiberGlass Master. If my Byron Pitts ever expires I know where my Saito 270 is going!!!


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