heli_Rod

SWEET! Very nice detail!

Rod

abufletcher

I have a confession. That's just a photo. I found a hi-res image of the Bentley BR2 through teh photo library of the Museum of Science and Industry in London (paid them a small processing fee) and then worked on the image a bit in photoshop. For example one of the cylinders had been cut open to expose the piston and I needed to fix this. Also I had to remove the background and the blue stand that was supporting it.

But I really do think that a high quality photograph behind a closed cowl may, in fact, look better than most of the dummy engines we see on scale models. If I decide that it doesn't have enough "depth" then I might lay down some surface detail like the rods and cylinder pins. In fact, I've already PS'ed an image with the rods removed from the photo and space for a built-up forward crankcase.

heli_Rod

Sure fooled me...LOl. It looked so real. Not a bad idea of using a flat graphic though. If you're not looking for absolute realism, it would be a great time and money saver along with being a no hassle maintenance detail. Something I never thought of before

Ole dawg just learned a new trick!

Rod

abufletcher

Another plus is that I can swap the static image for one of the engine rotating for flight. That way I can avoid that embarrassing scene in Flyboys where the aircraft's propellor is spinning but the "engine" is just sitting there. Here's the image of the Bentley as it would have looked in motion. I did this with photoshop based on video I've seen of a functioning 1/4 scale Bentley running on a bench.

abufletcher

Well, here it is. The fruits of a day's labor (well actually a night's labor and a day of waiting).

The bad news is that removing the laminations from the forms pretty much destoyed the saran wrap so I'm going to have to pull them off the board and rewrap them. Oh boy.

abufletcher

Man, I just knew there HAD to be an easier way than cellophane wrapping all the parts -- and there it was starring me right in the face. Tape. Cello-tape. Good old Scotch tape. I had all the parts recovered and nailed to the board again in about 5 minutes. It's almost ridiculously easy. Put the tape down the middle, then press down the sides.

Also instead of cellohane (which I really hate) to cover the board I used my trusty wax paper (which I've been using since I was building Guillow's models on my mom's kitchen table).

Time to get cracking on the second set!

abufletcher

Hmm...[]..the tape I'm using looks like it's decomposing in contact with the white glue! How is that possible? This is plastic right? Well, I've only done the one pattern tonight and we'll see tomorrow if enough of a barrier remains to be able to separate the laminations. Stay tuned.

khodges

My Feedback: (1)

Abu-- Lookin' good. I did a similar type linkage for my Bristol. I used carbon fiber rod and standard Futaba servo arms, and made the mount/pivot from brass tubing and brass plate. The brass tubing is a slide fit over the carbon tube, and is soldered to the brass plate, which is screwed to the fuse box. The carbon rod is cut to 1/16 less than the width of the fuse mount to limit side play, and I both Ca'd and used a 2-56 screw through the arms to bond them to the rod. Extremely lightweight and strong.

Reg Hinnant

My Feedback: (9)

Hey Don,
On the Sopwith Baby tail surfaces I was using MDF patterns to laminate to. All I did was use wax paper on the base and rub candle wax on the sides top & bottom of the pattern. I was laminating up 2 sets & had to use new wax paper & rub the candle on the form well both times. I was wetting the wood & using Gorilla glue.

abufletcher

khodges, thanks for the photos. Your set up looks really good. I suppose Chris' solution is fine for a kit (minimal materials, functional, and strong). I built something like you set up for the bellcrank on my Legionaire (which officially just used push-rods but I wasn't having any of THAT).

abufletcher

Very useful tips, Reg.

The good news is that when I checked today the tape method seems to have worked satisfactorily -- at least as well as the saran wrap method. But I think I might try the wax idea just to experiment a bit. I also picked up some Gorilla glue this summer so I think I'll give that a try.

abufletcher

Well, working with foaming glue was an interesting new experience. It initially looked awful but cleaned up really nice. It certainly cured faster than white glue -- but white glue might have more strength. It doesn't really matter here and the couple remaining laminations I'll do with the same tape + gorilla glue (actually the Elmer's brand of it which was a couple of bucks cheaper).

BTW, the bottle says it's 100% waterproof. And that's completely right. Waterproof. Soap-proof. Shampoo-proof. Alcohol-proof. And almost thinner-proof. This stuff does NOT come off your hands like white glue.

Two days later and I'm basically finished with the laminations. I have to redo a couple that didn't come out quite like I'd like but basically I'm ready to continue.

But...now that some replacement parts have come from Chris, I think I'm going to get back to building the fuselage. Then I can come back to the rudder and stab and have the "fun" of the laminations behind me.

abufletcher

Returning to the topic of engine choice, I'm still going back and forth between a Saito 56 and an OS 70 Surpass. The 56 is a better fit for the cowl (both in terms of height and depth). The OS (which is almost exactly the same size as the OS 60 drawn on the plans) would stick out the front just a bit too much for my tastes. I like to place the thrust washer about halfway out of the cowl. Some people may prefer a more forward placement.

But I wonder about the possible advantages in terms of weight and power of the 70. A lightly built 63" wingspan biplane ought to float fairly well and I would prefer to "fly it on the wing" than "drag it around by the prop." Still...

Reg Hinnant

My Feedback: (9)

The 56 looks good to me, Don.
After you start working with the polyureathane glue, you can judge the right amount to put on the wood to get a minimum of foaming. It does start to cure fast enough where you have to watch your time when you start. The foam has no strength, only the clamped material surface joint is strong. I find it sands good with no hard joint line like epoxy/ca. I also think that gorilla glue gives a slightly more flexable glue line than Elmers.
I apologise for negelecting to warn you about getting it on your hands or clothing. Its BAD.... And dont bend down & sniff the fumes either........[>:]

khodges

My Feedback: (1)

Consider the size of prop you can drive with the bigger engine. WWI planes had huge props (diameter) and models look, well..... dumb with a tiny little prop on them. Even the .70 wouldn't begin to turn a scale diameter prop, but the .56 is only good to about a 13, too small by far for your plane (at least as far as looks go). Of course, you can go to all the hassle of changing to a big oversize prop for display, but I figure the bigger prop looks better even when it's a spinning blur, and hey-- what's the throttle for, anyway?

I have a 16 inch prop on my DR-I, and scale is 21 inches (that's the GP ARF). No way the .91 Saito on the Tripe will spin a 21, and rpms are limited with the 16-5, but it flies fine, and looks better than the 13's and 14's I see on others. I have a 14 on my Bristol, and would have a 16 on it but the .80 won't turn it well enough to get decent performance, plus the engine overheats.

abufletcher

I put the fuse together again with rubber bands and tape to check the fit with the new parts (a wider tank area to accomodate a larger range of tanks and some minor fit adjustments) and everything looks really good!

CTDavies

Hi Abu,
here are a few images of a Snipe being built here in Germany. I got them this morning









The quality of the images isn't as good as yours, but I hope you like them anyway.

abufletcher

Mensch, das ist aber SUPER SCHNELLES Arbeiten! Ich soll mich beeilen!!! Very motivational. Thanks for posting these. I'm hoping to have my fuse done in a few days at most. Then it's on (back) to the rudder and stab.

And by all means invite the German builder to post here if he likes! Zumuetlich, spricht er auch ausgezeichnetes Englisch, aber wenn nicht, soll er ruehig auf Deutsch posten. Und fotos brauchen gar keine Worte! [8D]

Looks like he's decided to go with the late productioon Snipe. Does he have a particular color scheme in mind yet? I'd also be interested to hear which engine he's thinking of using.

abufletcher

Next step is to epoxy formers F1, F2, F3, and F4 to the right side. It's important to get these perfectly perpendicular. Actually, I cheated here and didn't epoxy in F4 until AFTER I put the two sides together. This was so I could be sure of the fit with the tank wall parts.

Make sure to add on the servo bearing beams and the rectangles of ply that will hold the elevator bellcrank. BTW, I cut new, slightly thicker, rectangles.

abufletcher

Now you can add the second side, making sure that everything lines up. Don't forget to build in the elevator bellcrank!

This step can be rather critical with regard to the placement of the tank wall and how it lines up with the wing tube. Here's what I did and what I suggest. First, attach the fuse side to formers F1, F2, and F3 (leave off F4 for now). When that's cured and solid, quickly in rapid succession do the following: 1) epoxy in the "top" of the tank by laying it down on F2 and F3; 2) epoxy in the tank wall; 3) slip in the wing tube to get the tank side properly aligned 4) add in F4; 5) adjust the fit of all the tank wall parts -- together with F4 which formed the end of the tank -- before the epoxy cures.

abufletcher

Oh, and here's a top view at this stage.

abufletcher

There are a couple things that you need to be aware of here. First, it would be all to easy to rush ahead and add in the ply rails for the bottom hatch and the slotted hardwood rail for the gear. BUT...this is sort of like a Chinese puzzle and you have to make sure you do things in the proper sequence. First, it will be hard to put in the aileron servo with the hardwood rail in place. Second, you can't put on the ply rails until you've put in the hardwood rail (and possibly not until you've attached the gear piano wires). Third, once you permanently attach the wing tube (thread and epoxy), THERE IS NO WAY TO REMOVE OR PUT IN THE TANK.

***UPDATE: Chris is aware of the tank problem. He suggests that the tube over the tank can just be cut away. I was thinking of maybe using small cotter pins to hold it in place.

So think strategically here!

Also the throttle and aileron servos are a very tight fit now that the tank area has been enlarged a bit to accomodate a wider range of tank sizes. It's very important to get the placement just right. I would recommend placing the throttle servo almost against the tank wall, while the aileron servo needs to be placed exactly in the middle. The current plans (which as of October 24th may not have been updated to reflect the larger tank area) show these two servos as being in a line.

Also the servo beams create a very close fit for the servo casing. Close enough that the rubber bit at the end of the servo wires WON'T fit without cutting a small notch in the beam. What I plan to do here is to cut a small notch with a chisel on the opposite end to where the servo will be located and then slide the servo over to its ideal location.

abufletcher

Next, since I don't have a fuse jig (as Chris shows on his Pup construction photos) I'm trying out a trick I learned from Donnie over on RCSB. You make a pattern of the inside of the rear fuse and use that to keep the sides equal. I'm experimenting with a lite ply version but you can also use blue foam. I still need to do a bit of careful thinking here.

abufletcher

It seemed best to go ahead and install the servos at this stage. As I said it's a tight fit -- so tight, in fact, that I needed to sand a bit of the width of the top servo beams -- as well as make a notch for the cord (using standard HiTec servos, see photo). Even miniscule discrepancies in the placement of the formers might have this effect. So be prepared.

As you can see, it's no longer possible for the throttle and aileron servo to be aligned. For the servo arm to line up with the hole in F2, the throttle servo needs to be all the way against the tank wall. The space for the aileron servo, on the other hand, allows for only a millimeter or so of clearance with the standard arm. I used this arm for placement of the servo. In actuality the servo arm will be pointing forward and will move perhaps about 45 degrees left and right of center.

Note, by setting up the "center point" of the arm to be at either 11 or 2 o'clock (I haven't figured out which yet) I should be able to get some differential on the aileron movement (i.e. more up than down). This is the result of some fundamental geometry of rotation to linear movement that I'm not even going to try to understand!

Dai Phan

My Feedback: (2)

Don,

Watching your progress makes me feel so bad! You can read from plans and put together the plane with ease making me wish I have the skill like you. Excellent work and looking foward to your completion. DP