Has anybody built the Balsa USA Bristol? Thos e of that have know how great their instruction handout is (Not). I'm currently working on the first wing half and have one question. There is no mention of rib #1 in the instructions or on the bill of material list. I have found what looks like 4-1/2 ribs that should be the choice to use as rib#1. I would like to have somebody else give me a head nod to confirm that I'm on the right track. The 1a rib piece also doesn't look quite right (seems a little small). There is really nothing else to put there.

why dont you call Balsa USA

I've got one, don't remember having any real problems building it; I thought it was pretty straightforward. i modified mine a bit; made the tail surfaces closer to true scale, and made pull-pull controls for all surfaces. I love to fly it, it's quick, agile and easy to fly. I have a .80 Saito in mine, so there is no lack of power. One of our club members flies his with a .46AX and it does fine.

I'll pull out my plans and book and see if I can assist.

Khodges:
Very slick pull-pull system! Can you give us a little more particulars about the parts, etc that you used? I'm also very interested in how you mounted it to the fuse sides. I see the screws, looks like they go into balsa, but that can't be all there is.
Thanks.

The rudder is your basic, 2-wire pull-pull, routed through the outer tubes of a flexible control rod setup (Sullivan Goldenrods). This allows more latitude in servo placement and the exit points of the wires through the fuse than you'd get running the wires straight from servo to control horn. The tubes can be routed to the desired exit points and secured to the framework just under the covering (Koverall on this plane). I wanted the servo ends of the wires to be on the centerline so I could make them all equal length to keep the geometry so that the wires stay taught and don't bind.

The elevator was the one that took some creative engineering, to allow one servo at the side of the fuse to control 2 sets of pull-pull wires, and keep the servo forward as possible for weight distribution. The crossways rod with the control arm is a carbon fiber rod; I drilled out the center of 2 servo control arms (DuBro heavy duty) and fit them over the rod, and pinned them with 2-56 screws as well as Ca. This way, the screws keep thwm from rotating on the rod if the CA gives. The single arm goes to a rod with ball joints to the servo. The double arm has ball-type swivel connectors to the wires that go to the elevator; these wires also feed through tubes for the same reason as the rudder's. You can see in the tail shot where they exit the fuse, which are scale locations on the M-1.

The carbon tube has to be free to rotate and is cut just about 1/8" shorter than the width of the fuse box so it has little side-play; I used brass tubing of an inside diameter just larger than the carbon rod. I made two "sleeves" with a flat brass plate soldered to one end of each. The sleeves are slid over each end of the rod and screwed to the sides of the fuse box structure in a location that allows the double arm to align with the tubes for the wires. The outside of the box has a small lite-ply plate with blind nuts where the sleeves mount. The servo, linked to the rod, rotates it back and forth to move the elevators. The wires are still adjustable for tension, and are equal length so that there is no change in tension with up and down movement of the control surface. If you look at the pic below, you can see where the c/g location is (marks on the edge of the wing saddle). The servos and Rx are all located near the c/g, the battery is under one end of the rod. This plane has a short front, so keeping the weight forward was a concern.

Very nice workmanship, I love looking at an aircraft that is well built. Very creative solution for the pull-pull system as well.

Cheers!

Jollidude

Thanks for the info. I called Balsa USA and found out that they must have shipped my kit without those two balsa sheets with #W1 ribs. Billy at Balsa USA said he would send me the sheets ASAP. Now that's what I call great service. I will buy a kit from Balsa USA in the future!

Wow.. I built almost the exact same assembly to open the tail wheel doors for my P51.. In my case I need an assembly that would change back and forth motion to up and down. It workes flawlessly.

Randy

Ok Guys I have another quick question. I'm working on the aileron and had two conflicting aileron leading edge processes. The construction guide has only a one 15/16 inch balsa aileron leading edge and the plans show two 15/16 balsa pieces that make up the leading edge. Which one is right?

Are you by chance looking at the view that shows this tapering? If I remember correctly the aileron spar tapers in height and width as you will find when you sand or shave the aileron spar down to fit. Hope this helps.

Jeb

I was wondering if there are two 15/16 inch leading edge pieces that make up the leading edge. I understand about the tampering from the root to the wing tip.

I JUST BOUGHT A BALSA USA BRISTOL M1.

I WILL APPRECIATE TIPS AND SUGGESTIONS ABOUT CONSTRUCTION AND ALSO FOR COVERING IT.

THANKS

gonna build mine this winter!

FA[8D]

I will be starting construction of my Bristol in a few weeks and I was wondering if anyone had powerplant suggestions. I have a Thunder Tiger .91 4-stroke. I would like to go with a 4-stroke but I don't need speed. A friend thought the .91 might be too much. Also, is it just me or is the engine mounting vauge on the plans for this bird?

Hello again everyone. Well, I'm back to my Bristol again after getting surgery on my right ankle. I'm in a cast for the next six weeks but it wont keep me from working on my planes. I figured out the aileron this past weekend and got it framed up. I cant believe this little section is kicking my butt. I've built several models and never had this much trouble. My son keeps asking me when I'm going to get done with that half of the wing. Nothing like having some pressure from the kids.

Yes, the mounting for the motor in this kit is vague.
You're supposed to mount your engine in your mount, just keeping the centerline of the drive
lined up with the plans. I imagine it'll need a couple-two-three degrees of right and down thrust, maybe not.
says .40 to .60 on plans, I'll probably use a .72 fs...... .91 does seem a little big.
Anyone heard any reports on the RCV four-strokes?

FA[8D]

I've got an .80 Saito in mine, it will take off in 10 feet, but it's perfect for dogfighting. I think anything from .65 up will work fine. I don't have any right or down thrust in mine, and I don't think it needs right thrust, dut a degree or so of down wouldn't hurt. It has a tendency to climb with power and I have a fair amount of down trim in mine which I have to change to suit the power application.

I plan on putting in a Saito .91 four stroke. I cant see putting in something that does sound like an old plane. I think the four strokes give it the authentic sounds of yester-year.

My .52 four stroke flys the plane very well. Having said that the plane does need nose weight or certainly everything forward of the cg with a light built up tail section. A larger motor would provide the much needed nose weight and the throttle stick on the transmitter makes us all even!

JEB

HI BPS, WOULD YOU PLEASE POST SOME PICTURES OF YOUR BIRD. IT WILL BE VERY INSTRUCTIVE FOR SOME OF US THAT WILL BEGIN TO BUILD THE BRISTOL. I WILL USE AN OS .70 SURPASS. I' PLANNING TO COVER IT WITH SOLARTEX.
ANY SUGGESTIONS FOR THE COCKPIT AND THE PILOT? SOME TIP ABOUT THE SCALE SPINNER?

THANK YOU ALL FOR SUPPORT ALL OF US WITH YOUR EXPERIENCE.

FERNANDO

BPS, how much nose wieght?

A .52 w/ nose weight, an .80., .70 surpass.....hmm. I do have a Saito 90R3 that's in reserve for the right plane
...definitely would add 'hutzpah' to this plane!

FA[8D]

No nose weight was required for my bird. I built the tail feathers from stick and was very careful about adding weight especialy aft of the cg. Someone once said of aircraft design, " if you must change something add simplicity and lightness". My plane is modled after the racer and the spinner was removed. This simplified my spinner problem. Having said that someone supplies a spinner in aluminum for this size Bristol, just can not remember who. It was pricy as I recall. I would suggest keeping the pilot and cockpit simple and light. I just painted mine and added a sport pilot figure from Williams Brothers. Built my own wheels as well. Here are some photos, and I will be happy to answere any questions I can.
JEB

Arizona Model Crafters has an Albatross spinner that works, about $70 as best I can remember (almost as much as the whole M-1 kit). It's not truly scale, although it's the right diameter. The Bristol's spinner is spherical, the Albatros is parabolic, but the difference at that scale is small.

I also changed my Bristol somewhat. I enlarged the horizontal tail to make it closer to scale, and stick built it instead of using the balsa slabs that come in the kit. It probably saved a couple of ounces in the rear.

What is the diameter of the 90R3? I bet that would be a great powerplant for the M-1D, of which there was only one built. It had a 3-cyl Franklin radial.

Very Nice build. I also am building a Bristol M1.c 1/6th scale. I'm using sweitzer quarter scale plans, reduced. I changed the airfoil as I didn't like the undercambered one shown in the plans. I also scratch built everything, including the wheels which I found to be very difficult. I built them 3.5" used a black 3/8" tubing and put a smaller one inside to support the outer tube. As you can see in the photos, the joints are rough. I'm not real happy with them. Could you explain how you built the wheels?

Sounds like I built my wheels much the same way that you did. For the center core i used a lightweight 1/2" foam filled pvc plastic called Sentra. I drilled the center hole first and then sawed a circle based on that center hole. After that i secured the part in a drill press using the center hole and shaped the outside diameter. A lot of work with a 1/2" round file with the wheel center in the drill press provided a nice deep groove for the tubing to set in. It took some experimentation to get the correct length on the tire which was made from automotive black tubing. Cutting the ends of this tube nice and square was a real job. After i got a nice fit then i fitted a smaller tube about 1/2" inside and put the entire tire on the center hub. Once satisfied with the fit Thin CA secured the entire unit. Sanding with fine grit paper smoothed the joint and the entire tire was sanded to complete this process. Then the raised portions of the center hub were created using balsa and the entire wheel was placed back on the drill press for shaping. Next added a small diameter nylon tube for the wheel hub bearing. had to drill the hole in the center hub just a little larger for this bearing. After that the tire was cleaned with acetone to bring back the nice black finish. Last step was to seal the balsa on the hub with dope and painted with red dope. Sounds like a lot of work and it was!<div></div><div>Hope this helps. My Bristol is now retired and hanging in my workshop as i have moved on to much larger aircraft. The Bristol was fun though.</div>