XXL Polaris scratch build

[benovisoff]

Vey nice. Well done

[Larry3215]

Thanks!

[Larry3215]

Ive been making some progress. The motor mount tail section is turning out ok. Im wishing I had done it differently now but this is working out.

Im starting on the hinging and elevator section next.

[Larry3215]

More progress....

I have the elevator section built and hinged but not mounted yet and I have the rudder cut and hinged in place.

I also recieved my roll of super slick tape and covered the bottom of the fuse where ever I expect contact. Its pretty nifty tape!

I decided to do a balance check. I said before that I wasnt too worried about balance, but every time I added something to the tail section I got a little more worried!

I just checked and it looks like I will be ok - barely! With the packs as far forward as they can go I should be just at the recommended CG.

Hopefully, by the time I get some colored tape and a little paint in it the CG wont shift toooo far back. There is a good chance Id want the cg back a little firther than where Steve recomends but its nice to have to wiggle room!

[Larry3215]

By the way I decided to do the rudder and vertical fin parts from Depron so save on paint/finishing headaches. The elevator is still 1/2 blue foam but the writing is on the bottom so it wont be so bad to cover.

Next is to attach the elevator and top fin then work on the motor cowling.

[Larry3215]

No new pics but Ive been making steady progress. I hope to have it ready to maiden this weekend!

By the way Larry - I tried some of that Tight Bond III to glass over the nose area and I like it! Its easy to do, no bad smells, drys reasonably fast and seems fairly hard and sands well.

[larryross]

Glad you like using the Tite Bond. One thing you do need to do is make sure you completely cover the cloth. The finish is hard... I have a giant hydro foamy that takes off on black top and there is very little friction. It is kind of noisy until it gets in the air.

I'm still fighting warpage on my main wing, but I think I have it under control finally.

Do you have a target weight yet?

My motor, ESC, and servos are on the way. I'm using a Trungy TR 35-48-C With a 1210 prop. Should be more than enough power.

I have most of the parts in primer ready for paint. I'm using overhead projector transparency for hinges. Also putting my elevator servo in the front of the plane and running a control cable back up through the fin to the elevator. As slow as I am It will be weeks yet for mine.

Originally Posted by Larry3215

No new pics but Ive been making steady progress. I hope to have it ready to maiden this weekend!

By the way Larry - I tried some of that Tight Bond III to glass over the nose area and I like it! Its easy to do, no bad smells, drys reasonably fast and seems fairly hard and sands well.

[Larry3215]

No idea on final weight - havent weighed anything yet. Im hoping for 5 pounds but expecting closer to 7. Thats around where my other large foamies have come in and this is a similar amount of foam and hardware.

Im not nearly as worried about the final weight as I am about CG. It will fly fine even if it ends up at 8 pounds. These big birds dont seem to care as much about the over all weight.

CG on the other hand....

Im glueing up the aileron hinges at the moment. When thats done I'll weight all the bits and see what it adds up to.

Yours is going to end up looking much better than mine. I'll be flying 'in the rough' compared to your finish job!

[larryross]

I expect mine to be around 6 lb +- 1lb. I too am worried about the CG, but as you said about the weight... I'll just put a bigger battery in the nose I think I have a big enough motor.

I have 3 planes that I am building right now that I want to finish to show what foamies can be. I was an auto body and fender man for 20 years so will apply some of my knowledge to a couple of planes then build more just to fly.

[Larry3215]

LOL

Yours will make mine look like the "before" photos the cops take at the scene of the crash and yours will be the "after" photos when it rolls out of the body shop

[CHELLIE]

Wow, Thats going to be a nice sea plane Larry, I dont know how i missed this thread Keep up the great work, Chellie

PS I agree with your Wife

[Larry3215]

LOL Well, we have been married long enough now that I finally have figured out that she IS always right!

I just weighed all the bits and pieces and Im currently at 6.34 pounds. That does not include the glue that will be needed to attach the rest of the tail section or any paint or covering material I decide to add.

I expect by the time Im all done I'll be very close to 7 pounds.

If I end up at 7 pounds then the wing loading will be in the neighborhood of 11 ounces/ft. I did a very rough calc on wing area and, including the fuse area, its around 1500 sq inches.

That puts it in the same cubic loading range as BUFY which is better than I expected. The wing loading is 1 ounce more than BUFY but the larger size makes the cubic loading work out to be the same.

It should be able to be flown in fairly tight spaces which is good. The pond I will use to test it out doesnt have a ton of excess flight space.

Im jazzed!

[larryross]

Ha Ha Ha I'm sure yours isn't going to look that bad ( I've seen some of your builds) and I'm sure mine wont look that good (this being the first model I have finished), but thanks for the kind words. I don't plan on stopping at covering the wing so the CG shouldn't change, but the plane will get an ounce or two heaver. I'm thinking that if the CG goes too far back I'll just put a motorcycle battery up in the nose.

Originally Posted by Larry3215

LOL

Yours will make mine look like the "before" photos the cops take at the scene of the crash and yours will be the "after" photos when it rolls out of the body shop

[CHELLIE]

Originally Posted by larryross

Ha Ha Ha I'm sure yours isn't going to look that bad ( I've seen some of your builds) and I'm sure mine wont look that good (this being the first model I have finished), but thanks for the kind words. I don't plan on stopping at covering the wing so the CG shouldn't change, but the plane will get an ounce or two heaver. I'm thinking that if the CG goes too far back I'll just put a motorcycle battery up in the nose.

Hi Larryross and Welcome to Wattflyers , lots of super nice people here, i like it here, and they even put up with me Take care and have fun, Chellie

[larryross]

Thanks Chellie

I have a daughter named Michelle and I have always called her Chellie. I don't get to see her much as she and her family lives 1000 miles away. I miss her and Grand kids a lot.

From what I have seen so far, I will have to agree about the nice people here. I think I have seen you on RCGroups a couple of times haven't I? I got here because I am building a 2X Polaris too and posting on RCGroups.

Later
Larry

[CHELLIE]

Originally Posted by larryross

Thanks Chellie

I have a daughter named Michelle and I have always called her Chellie. I don't get to see her much as she and her family lives 1000 miles away. I miss her and Grand kids a lot.

From what I have seen so far, I will have to agree about the nice people here. I think I have seen you on RCGroups a couple of times haven't I? I got here because I am building a 2X Polaris too and posting on RCGroups.

Later
Larry

Hi Larry Thats neet that you call your daughter Chellie , yes i am on RCG, RCU, Flying Giants and Wattflyers, but I like it here the best, thats just me, it seems more country to me Good luck to you on your 2X Polaris, Larry 3215 is one of the best of the best in this hobby, I know I have learned a lot from him, Take care, Chellie

[Larry3215]

Im getting close to being ready for the maiden!

Both wings are pretty much done. I have the tip floats on and glassed using the Tight Bond III.

Im liking that stuff a lot where strength is more important than weight. Its still lighter than using epoxy but and heavier than using WBPU but its much stronger than the WBPU I think. Easy to work with too. I also got the super slick tape on the tip floats and the servos and linkages all done.

All thats left to do on the wings is install the ply plates to run the screws thru to hold the wings on in flight.

I made up some fairings for the servos but Im not going to install them yet. I need to wait untill I know where the color is going on the wings so I can pre-finish them in a contrasting color.

I did a quick assembly of the wings to check balance again and it looks like Im still ok - barely.

One thing I realized is that THIS THING IS BIG!!! When you work on seperate pieces its hard to get a grasp for how large it really is. I shouldnt be surprized, the Mega grabbed me the same way when I finally got all the sections together. Its pretty cool though

Thius weekend is looking positive for good flying weather so I think its looking good!

Now all I have to do is finish up the tail sections and all the 643 other small details I havent done yet...

I wont add any color untill after the maiden.

Lets see if Chellie's trick works....

[larryross]

Larry
That is looking good. What are you talking about... mine isn't going to look that good. The maiden is this week end? Can't wait! No one else has build one this size that I know of. Do you know of any? Good luck.

[larryross]

If you are going to use this where you need strength, use a bamboo skewer and poke many holes in the facing surfaces. Do not poke all the way through only about half way. This will give the glue extra bite and help strengthen the foam and make the bond deeper. instead of just a surface bond. Try it you'll like it. Great when using Gorilla glue and others too.

[Larry3215]

Thats a great idea! I have one of those roller wheels used to poke holes in balsa that should work great for that too.

[larryross]

I've been meaning to get one of those. It would be faster and easier than the skewer.

[Larry3215]

Oh - I forgot to answer your other question - I dont know of anyone else building a 2x Polaris other than the two of us.

I think someone was doing one in the 120-125% range, but thats small time stuff

[Larry3215]

Originally Posted by larryross

I've been meaning to get one of those. It would be faster and easier than the skewer.

Well, I just wasted 5 minutes looking for mine and ended up grabbing a bamboo skewer!

[larryross]

Larry
I don't know If I mentioned it before, but I am building a 120% along side of my 200%. I'm not sure why I decided to do that. I guess I didn't think I had enough to do? . I just noticed, you aren't using a horizontal stab/elevator. What is that going to do for slow flying. In the original plans the elevator is in the direct prop blast won't this affect the flying characteristics especially at slow speeds and short take offs? Have you seen my BE 103 Build here http://www.rcgroups.com/forums/showthread.php?t=980653

I am building it 48" and if I like it, I will go for a 72" after I do a mega Cap.

[Larry3215]

Originally Posted by larryross

Larry
I don't know If I mentioned it before, but I am building a 120% along side of my 200%. I'm not sure why I decided to do that. I guess I didn't think I had enough to do? . I just noticed, you aren't using a horizontal stab/elevator. What is that going to do for slow flying. In the original plans the elevator is in the direct prop blast won't this affect the flying characteristics especially at slow speeds and short take offs? Have you seen my BE 103 Build here http://www.rcgroups.com/forums/showthread.php?t=980653

I am building it 48" and if I like it, I will go for a 72" after I do a mega Cap.

Yeah, I saw your 120% - I was just teasing you

I am going to have a horizontal tail on it - just havent glued it on yet. The fuse is so long its enough trouble moving it around my small shop as it is! Im not going to glue it on or the top rudder/fin until the last second.

That will happen tonight! Im still mentally debating on the final details of the top fin but Ive about worked that all out.

Im going to glue the fin and elevator on tonight and then do a final CG check. That will tell me where my battery hatch needs to go so I can cut it out.

That should be the last thing I must do before it can fly, so with a litle luck I will still make it by tomorrow. Sunday for sure!