P-40 DRIVER

well I screwed that post up.

cubcrasher

My Feedback: (6)

P-40,
Looks like it turned out nice.

P-40 DRIVER

cubcrasher: thanks, except for not having enough elevator to three point it. All is well.

P-40 DRIVER

Update on the Cub, Still flying well, plenty of power with Magnum 52 which is broken in now and running well. Ended up putting a little weight in tail so it would three point properly. Tail surfaces warped on me because I got them to thin by sanding to much. I straightened them out with a heat gun this evening and we will see how that works out. Because I'm not using 40oz servos in this thing, do to what was available at the time, My trusted Futaba 600 mil amp NiCad battery packs I've been using forever are having a bit to much voltage drop for my liking, I have ordered a high drain 4 cell pack from Hangtime hobbies which should solve the problem. Same weight, more capacity, and going from 16 ohms internal resistance to 7. Easier to deal with then LiFe packs to. I still have not decorated the plane, For its main purpose, is a test bed, and gives me something to fly once a month while I build my Sig 1/4 CW Cub. Fuse is built and I'm starting on the wing. I recently bought a Tactic 8 channel radio through Tower for $129 including a receiver, works well in the Cub, more on that later.

P-40 DRIVER

Started decorating the plane finally. N numbers, cub decal, spats, and the racing stripe should make the cub look a bit better.

P-40 DRIVER

I have cycled and installed my new battery; moving it aft to back of the passenger compartment. this has allowed me to remove the tail weight I had on the plane. These Sanyo Elite cells really perform, I was able to pull a .5 amp load for most of the batteries capacity without dropping below 4.8 volts. I have also installed the Spats. My black trim sheet is on its way from tower for the stripe.

cubcrasher

My Feedback: (6)

Hey P40,
I been eyeballing that Tactic outfit also, looks
like a pretty good deal. I went gas on all my bigger planes. I put
DLE 20's on both my 1/4 Cubs. Snap a couple pictures of your
new build.

P-40 DRIVER

Hey Cubcrasher, I'm planning on doing a full build with a bunch of pictures on the 1/4 scale cub as soon as I can my act together, The fuselage is framed and I'm starting on the wing. The engine is still up in the air. Do you have a Sig cub; and if so, how did you do the DL20? It looks like you would have to cut a hole in the firewall to allow for the carb. I think the Tactic radio is a steal right now, I think you can get the 8 channel through Tower with a receiver for $125.00. It has a lot of outstanding features but I will give the downside. If you fly with a pinch finger/ two finger style and you have big hands, you may find the sticks to low and the switches in the way. The radio will overload your receiver on the bench if its to close and cause the servos to be jerky. The potentiometer wiring; on the gimbles, moves when you move the sticks unlike a Futaba which stay still. A potential failure point maybe. This was an issue on some Airtronics radios, but it is wired better on the Tactic. Other then that its a great radio so far. Very easy setup and tons of features. The best part is the receivers are very inexpensive.

P-40 DRIVER

Update on my battery situation, It has become obvious you can't fast charge these NiMH batteries without cooking them to some degree and I don't have a temperature sensor on my charger so we are going to have stick with trickle charging completely. Not an issue with my NiCads. I will need to ponder this further, but may end up going back to NiCads or LiFe on the next buy. I don't think NiMH is going to be my final choice. NiCad is the perfect solution for me except for the weight and disposal. My main complaint with LiFe is if you leave the battery on to long, your buying a new pack.

cubcrasher

My Feedback: (6)

I built both Sig 1/4 cubs. The long wing had a Magnum 91FS on it the c/w had a Magnum 180FS on it. When I went gas
I did the long wing one first. I made the front of the fuse squared off, meaning I did away with that slope at the bottom. I went with a hanger nine
engine mount.{ HAN501015} The engine was mounted as close to the firewall as I could get it with just enough room to work the choke
butterfly. With the fuse done like this that gives you room to move the cowl forward without exposing that slope at the bottom of the fuse. When I
built the C/W I built the fuse like that from the get go because that 180FS was longer from the firewall to prop hub. This was easier than
moving the firewall back. Worked like a champ.

cubcrasher

My Feedback: (6)

Oh yeah, those DLE20's fly em real sweet.

P-40 DRIVER

My initial plan was to make the plane as lite as possible and put a Magnum .91 on the front. How did yours fly and how heavy was it?

cubcrasher

My Feedback: (6)

It came out about 14lbs. It flew really nice. The c/w with the 180 on it wasn't much heavier.

P-40 DRIVER

Thanks for the info, I'm hoping for 12 pounds, we will see

P-40 DRIVER

I'm moving this over to my new build thread for 1/4 scale CW Cub. THX

P-40 DRIVER

Just an update. the horizontal stab warped due me sanding it to thin. I was able to straighten it out with a heat gun for the most part. I did a successful test of my Tactic 8 channel radio. It works fine, but I'm not sold on the ergonomics of the radio, so my 6EX is back in the plane. I replaced the Hitec 485's with 422's so I can use 485's in my 1/4 scale cub. I did manage to install the stripe, N numbers etc. This made the plane look a whole lot better without adding any weight. I installed a spinner nut which should help with my electric starter and looks better to. Some of those LiFe Hobby King Nanotek Packs maybe in my future; Their cheap so I can ruin one now and again and not feel bad.

P-40 DRIVER

Update on my battery situation, I have gone to 1c fast charge which has solved the problem of my battery getting to hot. It appears on a 1/2c charge of my Sanyo elite 1500 mil amp cells that the battery does not dip 5mv distinctly enough, but is okay at 1c charge. I still prefer to 1/10c charge but being able to fast charge is important. So problem solved. The next thing I want to do is make the battery removable so I can use it in multiple planes. I don't fly much, so batteries sitting around slowly going bad is a problem, so having fewer batteries would cost less.

dtilney

I'm building the 25th anniversary CG cub. Unfortunately my firewall didn't come with the motor mount drill hole locations stamped in. According to the plans, the top of the upper mount is about 3/8" from the top of the fire wall, but I don't know how much to position it left or right. I'm installing a new O.S. 55AX Max. Additionally, the instructions don't mention anything about thrust angle. I appreciate any feed back!

P-40 DRIVER

Offset is 1/4" to the left from the pilots point of view. The right thrust is about 2 degrees. A 10# washer or Two under one side of the motor mount should get you there. I used a Great plains motor mount on mine though.

spaceworm

Hi. I have a nib Goldberg anniv cub kit. I plan to put a Saito 56 on it. Is the great planes 1/5 scale cub kit the same plane? The box looks the same except for gp vice gb. Did great planes absorb ? thanks.

spaceworm

Hi. I have a nib (duplicate post)

P-40 DRIVER

They are completely different airplanes. The Goldberg is 1/5.5 scale airplane which Goldberg started kitting in the late 1980's, if my memory is correct. Great Planes bought out Goldberg awhile ago, and the Cub is one of the few remaining kits, of his they still sell. The .40 size GP cub is the same size but was developed much later and is a bit more up to date. The current Goldberg cub is does not use the stamping dies of the original; which means, there is a few minor issues in the build. Hope that helps.

dtilney

Thank you P-40 Driver. Should I used a sideways mount as the plans show, I'd need to cut away at the fuse to get the muffler to fit. But by positioning the motor rightside up, I can fit it just fine without having to cut the fuse. Any caveats to using an upright mount (glow plug on top) as opposed to the sideways mount per the instructions?

I_Fly

I had one of these cubs for many years. My understanding is that the current kit is largely the same except the laser cutting and some minor quality issues.

For the engine offset you can do some geometry. essentially the right thrust angle is about two degrees. So plugging the angle and distance from the fire wall into the appropriate trigonometry formula and multiply by the distance from prop to firewall. If my memory is correct it would be sin(2deg) multiplied times the distance to the firewall.

For the engine mounting I had an OS 2 stroke mounted on it's side (exhaust pointing down) for many years. My experience is that 4 strokes would run this way as well. I have an FA-115 mounted upside down in a mustang and it runs great. A pitts style muffler is required for a two stroke. Some kind of adapter must be required for a 4 stroke if you want to use the muffler. A straight pipe out the bottom may be a good option for your setup. 4 stroke engines are not very loud without the muffler.

This is a great flying fun plane. Enjoy it!

P-40 DRIVER

The only issue would be the relationship between the gas tank and the carburetor. Better to run the engine invertered. Your OS 55 should run upside down just fine.