radfordc

My Feedback: (14)

I mounted my weights on the engine standoffs.

Corsair2013

My Feedback: (2)

I agree, unless you have a really heavy duty cowl, which the Skyshark is paper thin, I only mount the weight to a good structure.

Last night I went "Texas chainsaw massacre" on the Skyshark............

Took everything back out and cleaned up some supports I put in, took out the redwing power board, removed a wood panel I had put in, drilled holes to lighten the wood mount for the tail wheel servo, and pretty much started to lighten the plane.

I used some epoxy in the tail area to try and strengthen it but I was sloppy so I will be going into that area next and grinding out some of the extra that I am sure is adding weight to the tail.

I know I will be heavier than most since I put in a choke servo and tail wheel servo. I may move the gas tank, which is inside the motor mount, back to the area in front of the servo tray and put my batteries up inside there. I have to see how much balance weight will save me.

I also have a Satellite RX in the tail area which I will move a little forward. I know each gram in the tail adds many grams up front so I will thin it all out today.

I don't know what else I can do to get the weight down as my components are the same as everyone else. I wonder if the Sierra retracts are different since I just purchased mine this year and they were a little different design. Not sure what the weight difference would be.

I did have problems with the retracts as they were longer than normal as I had to modify the wheel well opening some.

Who knows, but I will get out what I can.

Keith

radfordc

My Feedback: (14)

The main thing I did was to keep as much weight out of the tail as possible. I mounted the rudder servo forward and used pull-pull cables and used a light weight tail wheel retract system.

RAMFlyer

My Feedback: (65)

radfordc, what tail retract system did you use?

radfordc

My Feedback: (14)

It's a homemade version of the Robart tailwheel. Looks like this:

radfordc

My Feedback: (14)

Here is a drawing of my version.

RAMFlyer

My Feedback: (65)

Great Idea!!! Thank you very much for the drawings...

Corsair2013

My Feedback: (2)

Nice tail wheel !!! I wish I had your talent in the CAD and building.

A little update - I took out around 9 ounces of material from the plane. Not much, so I guess the main weight is in the retracts.

I took out the gas tank and will be moving the two A123 LiFe 2300 ma batteries farther forward.

Should I be worried about putting the two batteries on top of the gas tank? They won't be attached to it but if I have the plane upside down and have a leak the gas could get onto the batteries.

I might put them in plastic bags, at least that would keep most of the gas off them in case of a leak.

I moved the Satellite RX forward and the air tank about 2 inches forward so maybe that will help a little bit on the CG weight. If I can get the two batteries all the way forward that should help also. Before they were right on the CG mark - 3 3/4".

Once I get the wiring all neat and nice and the RX mounted I will put her back together and do another Weight and Balance.

One thing I did do was to remove all the air lines and put in new colored lines with new "T"s. I am using the 1/8" quick connect instead of the barb connect. I kept having leaks on the barbs even with tie-wrap around them or safety wire.

It is sort of funny- it took me months to get everything put together inside. I took everything out and fixed it and put it all back inside in two days.............

Once the insides are finished then it is back to install the tail wheel doors, set up all throws, test air system, range test, run engine again, then it will be time for the maiden!

I still need to find a pilot in the area who can go on the buddy box with me for the maiden.

Keith

Corsair2013

My Feedback: (2)

Here are some new pictures after the "chain saw massacre".

I took everything out of the fuselage and cleaned it up. Ground out any extra Epoxy or glue, took out all the tubes for the rudder, elevator, and rudder control rods, took out the wood mount for the Redwing Power board and took out the board.

I may put the power board back in, but use Velcro and foam instead of wood to mount it. Took out about 4 ounces of double sided tape - went a little crazy with that holding the wires and air/fuel lines. Will use just a few foam holders instead.

I still have to figure out if I can mount the LiFe batteries up inside the engine mount box along with the gas tank or I might change the way the tank mounts or even get a smaller tank as the one I have will hold way more fuel than I will need, even with emergency extra.

The tail gear doors are ready to be mounted and connected.

The new airlines are colorful- will get a couple of good quality "T"s tomorrow and then do the leak test again.

I have a new partner who is helping me with selecting the correct paint and the correct way HOW to paint so that should really make a bid difference in how she comes out in the end.

Still plan on a few flights before I do any detailing. I may even wait until winter just so I can fly and not worry about building. Will see on that.

Keith

Corsair2013

My Feedback: (2)

I had what I think was a brain storm or maybe it was a brain cramp today. I was looking for an area to mount the ignition so I can make a plate to mount the balance weights above the engine when I noticed the bottom of the fuselage. All that extra space just sitting there behind a little bit of fiberglass.

Plenty of room to beef it up with some ply and add the batteries, ignition, and even some weight if needed.

Decided to make a fiberglass plug from the fuselage so that I can make a INSERT / DOOR. Once in get inside I will see if I need to reinforce anything since I am taking the panel out.

I still want to move as much weight forward as I can so hopefully with the batteries and ignition - 400 grams that far forward I shouldn't need that much dead weight.


Keith

kenair

My Feedback: (10)

I glued in a new servo rail ahead on the stock one in the fuselage, hope this helps with the amount of nose weight required. Like your posts. Cheers, ken

Corsair2013

My Feedback: (2)

Thats a good idea. If i still need balance weight i might give it a try.

If anyone has pics of your plane please feel free to post here.

I have 90% of wiring all neat now. Made the door and mounted batteries. Have more room for weight if needed.

I made a mold for the Powdered Steel Epoxy and will make ingots tomorrow. I will mount them along firewall and inside by batteries if needed. Will do balance again tomorrow.

K

Corsair2013

My Feedback: (2)

I have the battery hatch opened up and it will easily fit my two LiFe batteries plus weight if I need it.

I am about done with cleaning up the wiring so all I need to do is finish the air lines - add the 1/8" quick "T" and close it up and do another Weight & Balance.

I hope to come in around 3 lbs weight hopefully less.

When I started the build I weighed each component and yesterday I added them all up. The weight came in at 21 lbs. That does NOT include the Sierra gear so the retracts are what is adding all the extra weight. As I mentioned before these were the last set Sierra had so I think they are different than previous versions.

It is what it is as I can't do any more to change the weight so I will just move the balance weight as far forward as possible to keep the total weight down.

Here are some pics - I forgot to take a picture of the door so I will do that after I mount it.


I will make my weights in the mold then mount them to the engine box on the sides - I per side. Then if I need more I will probably make a box or something that bolts to the engine mount bolts and extend it forward.

I have most of the wiring cleaned up and the RX mounted.

Keith

Corsair2013

My Feedback: (2)

I did another weight and balance and have reduced the required weight down to around 3 lbs. I think I can use even less as I have a way to mount some steel angle brackets to the motor mounts screws and mount my weights to the bracket. This moves the weights about 6 inches forward of where I had the weights during the test.

I made up some weights with Powdered Steel and Z Poxy and it worked really well. I still need to work on the ratio of Epoxy to powder as I think I could have added more powder to the Epoxy. I was worried that too much powder would make the block brittle and with vibration it could shatter or crack.

I mixed 40 grams of Resin and 40 grams of Hardner with 650 grams of powder - roughly 8:1 ratio. The blocks came our hard and I don't think there will be any issues. The problem is that I wanted them heavier than they are so I wouldn't need as much mass.

I may go back and try 11:1 or 13:1 ratio with a small batch and see how it comes out.

Here are some pictures. I am waiting for the wife to get back from town - Home Depot - with my angle brackets. I can then mount a couple of the blocks and do another weight and balance.

Keith

Corsair2013

My Feedback: (2)

I mounted the weights today and ended up using much less than I thought. I actually may be a little nose heavy so I want to test with retracts up/down.

Here are a couple pictures of the blocks mounted. I had to cut one block in half and file down some corners so that it wouldn't rub on the Cowl.

I should have a final balance today and get a Total Weight.

Keith

Bosco2

My Feedback: (42)

Hey Keith

Its looks like you are comming along real well, I was thinking of setting up my ballance weight just the way
you have it then desided no I did not want to attach any thing to the engine with that amount weight attach to the engine in the event of a crash
it would wipe out the casing of the engine, The Skyshark was design around the G 62 or the Evolution I used a DA 50 had it in stock and with the
three blade prop, Im getting 6200 rpm the pull feels good it will fly the plane, total weight not sure yet, You can see how I added the front weight,

Corsair2013

My Feedback: (2)

Bosco - I like the way you mounted the weight - are those steel plates?

There is that chance of damage but if I hit that hard to drive those weights into the engine then I doubt there will be much left of the fuselage. I have seen many others mount the weight the same way..

I am pretty sure the engine mount - wood - will fracture like a crush zone = at least that is what I have seen in the past. I DON"T plan on any crashes -------

My total weight came in at 26 lbs 2 oz. Much better than before. I think I can live with this weight now. The 29 lbs had me very worried.

When I ran the engine last week I was right at 6300 RPM with my two blade. I am running rich so probably could thin it out some but she throttled up and down just fine. I will have one the experienced engine flyers double check the tune prior to maiden since this is my first liquid engine. I am running the 50cc Revolution Engine so I doubt it is as powerful as the Evolution 50. This is a low cost motor so probably not the best. If I put a 62 in it then I am sure I wouldn't need any nose weight at all and she would probably "literally" fly the wings off at WOT>........

I know on my future builds everything will go forward - very easy to add small amounts of weight to the tail to balance and not add much overall weight.

I also know I doubt I will buy any more ARF planes. I could have built three from scratch in the same time as this one. I would do one thing then figure out I should have gone on in a different order so I was always tight on space to tighten a nut or run a wire.

The best thing I did last week was just to take everything out and start over. I did learn tons on this baby.

This will be my everyday plane. I want to use this one for testing and practice so this year I won't be doing any detailing. I am going to fly the wings off this girl until I get really good at take off and landing. Then I will start the detailing.

Did you put in a cockpit kit? If so , post some pics.

The weather is warming up so as soon as the field dries out I will have her out there.

All I have remaining is to mount the gear doors, mount the nacelles, and the Canopy. Set up all the throws again and she will be ready to fly.

I will post some video and pictures when I get her out.

Keith

radfordc

My Feedback: (14)

I botched a takeoff and put mine in on the nose from 10 feet high. The wood motor mount was driven back into the fuselage...the fiberglass provided the "crumple zone". I rebuilt the front of the fuselage and reused the wood mount.

Corsair2013

My Feedback: (2)

Radfordc - Sorry you crashed but at least you were able to fix it.

Good to know about the fiberglass. I am sure it all depends on how hard you hit but yours looks like it took a pretty good whack!

Question? Did you have to fix any of the fiberglass on the fuselage? I was just putting some 2 oz cloth around the tail wheel opening to beef it up and am using the West system and for the life of me I couldn't get the cloth to stick to the fuselage fiberglass. I sanded it and cleaned it prior to this just like I always do.

Do you use anything other than denatured Alcohol to clean the fuselage?

Keith

Bosco2

My Feedback: (42)

Yes,

1/8 thick steel plates X 3'' painted and two kendorft fitting under engine can add more weight under the engine if needed,
Did the taxi thing sunday to see if anything would come loose or fall apart had to improve two small things and I could not belive
how well it handel on the ground, came close to take it up,

radfordc

My Feedback: (14)

I cleaned the inside of the fuselage with acetone and also sanded everywhere I applied glass cloth. I used epoxy and glass to make the repairs and so far it's holding.

Corsair2013

My Feedback: (2)

I remembered last night that I made a couple of fiberglass tail wheel covers and I waxed the whole area. I guess I didn't clean it enough so I went back again with acetone, sandpaper, alcohol and then applied the glass. It stuck better but still not like normal so I guess that wax really was built up.

Should be fine as I put some wax paper over the cloth then some wood pieces and clamped it all up. I will go back and apply some more epoxy if needed but it should be fine and I can mount my tail wheel doors. That area of my fuselage was really thin so I was worried with opening and closing of the tail wheel doors that I would crack the fiberglass as thin as it was.


K

kenair

My Feedback: (10)

The r/c, air, fuel and ignition installations in the fuselage are 98% done, just waiting for a fuel dot.


I add this plastic sheet cover over the servoes, held on by a srew in each corner to s small wood block. I find the plastic cover stops the air lines and the servoe lead extensions for the ailerons and flaps from falling into the fuselage servoes, saw this in a TF P-47 in Phoenix, so I borrowed the idea.


Just need to add the aileron and flap horns and pushrods.
cheers - ken

Corsair2013

My Feedback: (2)

Looks Great Ken! I like that idea. I ended up putting all my electrical and air under the servo's and tied them up. I used to work on the full size planes and was an Avionics Technician so I used to install all the electrical goodies in the cockpit. Many moons ago we used a special string to tie up all the electrical wiring. This string was wax coated and very light compared to using plastic tie wraps.

So now I use Dental Floss - works great and you just daisy chain it along the electrical bundle. That keeps them nice and neat.

I also use dental floss to secure most of the electrical connectors. If you use one strand then if you crash it will break when a wing or something comes off. If you use double normally that won't break.

OBSERVATION: Look at your Engine Box and then compare it against Bosco and myself - I guess it is the engine designs but my mount does not extend as far as yours and Bosco but my Cowl still is 1/8" from the Spinner back plate and everything aligns.

I finished the Nacelles and have the tail gear doors mounted. I still need to go back and epoxy the hinge a little more on both tail doors as I just tacked them in place until I was sure they were aligned properly. I picked up some new 1/8" quick connect "T" fittings for the air lines so that is finished. I have it pressurized right now and will check for leaks. I don't have very good luck with the plastic or brass barb "T"s. The seem to always bubble just a little bit even with tie wraps or safety wire.

These are $ 9.00 each but they don't leak.

Heading back to fix a broken LED wire that lights when power is on. Then tomorrow will be setting throws and taxi test down the road.

If the weather stays warm the flying field should dry out and I can get her out.

Keith

Lifer

My Feedback: (1)

HK sells air "T's" that are aluminum triangles with brass fittings. Zero leaks and about $1 apeice, as I remember.