SJN

yep...gives the epoxy some extra bite with the drilled dimples :-)

Hardware is fine.

SJN

...

DragonHeart

A quick question,

Whats the best way of crimping a closed loop cable ? ive never done one before i had a quick attempt today but the wire still came out................

[X(]

SJN

no idea.....thats why i used the carbon rods instead [8D]


anyone else ?

RRCKing

Hi all, I to am building one of these yaks and after reading all thats out there have decided to try and lighten up the plane as much as possible. One comment I would like to suggest is to replace the landing gear bolts with nylon ones. I have already read of one of these planes having the landing gear and mounting block ripped out on a bad landing. I have been using nylon bolts on the gear of all my planes for some time just because of this happening. It is less weight and if something bad happens usually you just have to replace the nylon bolts that tend to sheer the heads off the bolts. Also with all the neg. feedback on this plane I think its great that some of us are willing to try and make this beautiful bird fly. Mark

SJN

A good ide on the nylon bolts..... ist a pain is the gear block rips out ...i guess

How are you going to lighten it up ?

My plane is quite tail heavy......but thats the design of the plane...long tail, and very short nose.... ill probably have to use about 20 oz or 500g`s of lead in the nose of mine to balance :-(

Volfy

My Feedback: (23)

I have a Molex crimper for small wire connectors. I use it for making custom RC battery pack and servo connetors. It neatly fold the two metal tabs around the bare wire threads and fold them tightly into the center. This also works great for crimping pull-pull cables, because the folding action wraps the round pull-pull cable very tightly. Followed up with some CA, and the cable will break before the crimp will fail. IF you just use a pair of flat nose pliers and simply "crush" the crimp tubing, you'd be gripping the cables on two sides, and the cables can wiggle loose.

Volfy

My Feedback: (23)

SJN, how far out does your prop hub protrude from the fromt face of the round cowl? As I mentioned before, I am going to mount my engine farther out than specified, both to be more true-to-scale and to help with the tail-heavy tendency.

SJN

well, about 8mm ( 0.31496063 inch)
but if you look at the real one, the spinner goes behind the prop, and is also nearly flush with the cowl :-)
The picture you have is without the spinner.

But its a good idea....I wonder how much leverige it gives extra pr mm to move the engine further forward.

RRCKing

Hi SJN, Here are some of the ways I am shaving weight off this plane. Bear in mind I have just started on this thing and havent really began to get after it. I will inlarge the holes in the servo tray with a new stepped bit and clean up around the others on the fuse and wings with a drimel. I think I'm going to remove the bottom covering from the wing to gain access to the inside to remove more wood where its not stucturely nessecery. I have also removed the canopy tub except were it is needed for mounting.Also did you recieve one of these notices with the plane. Mark

RRCKing

Last pic.

Volfy

My Feedback: (23)

SJN, the middle picture you showed has what looks like an extension to fill the gap behind the spinner, The picture I posted doesn't have this extension. I was looking more at where the prop is relative to the cowl.

As for the CG change, you are probably right it won't change much. But I figure every bit helps.

SJN

hmm....no, i didn`t get the notice sheet.......but thasts because i bought my plane from Jamara in germany.

Volfy, have you trid to balance your plane yet ?
if you use the 44,5mm x .28 = 12,46cm or 4.9" That is very hard to obtain. That would take about 830g or 30oz of lead in the cowl to make it balance mine . [:@]

might as well have put an 80cc gas engine in it to make it balance :-)

SJN

this is at 13cm or 5,1"

SJN

on the first picture it looks like I have gobs of down thrust...... but it must be the cowl maing it look like that...

Volfy

My Feedback: (23)

SJN, I haven't had much time to work on my two GSP aerobats so far this week. I hope to get some time tomorrow.

Even 20 Oz. is too much, I know your Saito is a lightweight engine. My MVVS 1.6 with Pitts muffler weighs around 40 Oz. I figure I would use a heavy APC prop and probably the 4" spinner that comes with the GP Patty Wagstaff and Christen Eagle (I've got a couple of those lying around and they are fairly heavy). I think I will have around 3lbs for the entire engine assembly. Add the weight of the cowl and the GP 1.20-1.80 mount, and I may potentially have 3.75 to 4 lbs total weight hanging off the front end.

About the CG, since the wings are tapered, I don't think you would measure 28% back from the LE at the wing root. I will try to figure out where 28% should be when I get home tonight.

About the notice, I didn't get one either. I went ahead and used the 'CA' type hinge inlcuded... shuks! Being round, they didn't look exactly like the typical square CA hinges included in most other kits, but the material does look like fabric covered mylar. I have come across ARFs that came with clear (transparent) mylar pieces used to hold the control surfaces in place. I knew better than to use those. Oh well, for the time being, I am not going to worry about it. I will rehinge as soon as I spot trouble.

RRking, what do your CA hinges look like?

RRCKing

Volfy my hinges are the round ones also and I thought they looked ok but since the CA hinges are so cheap I went ahead and got some name brand ones just to maybe save the hassel of a redue. I think since I don't have the motor bought yet I will install all the servos battery and such,lighten everything then hang weight from the nose to determine the weight I need in a motor I sure like the looks of these new mvvs 1.60 gas motors.Mark

Volfy

My Feedback: (23)

My MVVS 1.60 are the glow version. I've got one already mounted on the GSP Extra 72" shown in post #17. I don't think the gas version has enough power on this airframe.

SJN

installed the throttle servo...

SJN

batt...

Volfy

My Feedback: (23)

Good idea to move the throttle servo. May not make much of a difference, but every bit helps. Plus it sure simplfies the throttle linkage on that Saito.

Okay, I'm trying hard to catch up to you. I got the engine mounted. I chose the MDS instead because it weighs a few Oz. more than the MVVS 1.60 Glow. I sliced the stock motor mount plate in half at about 2deg angle. I figure it probably has a net 1/2 to 1 deg downthrust. I may also dial in a bit of right thrust later if necessary. With the GP motor mount, I set the prop hub at about 13mm farther out than the instruction specified.

Volfy

My Feedback: (23)

Now, the all important question: how does it CG? With the engine, Pitts muffler, 17x8 APC, 3" GP spinner, as well as the main gear, wing and empennage "dry-fitted", the assembly CGs roughly at the wing tube, which is about 5mm behind the 152mm specified in the instructions. If I can make the rest of the components cancel each other out, I will be ecstatic.

It will be tough to finish out not needing lead, but I think I have a fighting chance if I:

1. Jam against the firewall a 5-cell RX battery pack, my usual on-board glow driver with a single Sub-C cell, and a 20 or 24 Oz. tank.
2. Use no epoxy to glue on the horizontal stabs, and just use two screws into the alum. tube to fix them in position.
3. Use lightweight elevator pushrods.
4. Use heavier main wheels.
5. Relocate the throttle servo as SJN did.
6. Lighten rear portion of canopy base or cockpit.
7. LIVE WITH A SLIGHTLY REARWARD CG.

BTW, the engine clears the cowl no problem. The muffler looks like it will be close. I have a smaller volume Pitts for this engine if this big one doesn't clear the cowl.

SJN

Looks good Volfy

but where is your cg now?

you must have picked it up just to check :-)

Volfy

My Feedback: (23)

Sonnich, I did pick it up. I was dying to know how it CG'ed so far. Equipped as shown in the pics, it balances within the width of the wing tube. It's just a rough finger tip test, but I estimate CG to be 155~160mm behind the wing LE. Not too bad.

For the CG test, I couldn't leave the Pitts muffler attached to the engine and install the cowl at the same time, so I just put the muffler loose inside the cowl about where it will be installed. It should be pretty close. I still have quite a few parts I haven't installed, so the CG could still tilt either way.

I can switch to a slightly heavier 18x6 APC if need be. A heavy brass prop nut will help, too. Things that stick all the way out front make much more of a difference. I would even go to a 3-1/2" spinner if required. I tried a 4" and it was way too big, but 3-1/2" should look okay. An elongated spinner like the Ultimate style should also weigh more.

RRCKing

Hi all I thought I would share this pic with you I am hollowing out the counter weights in the elevators and rudder. This is pretty easy to do and should help with the CG issue. Mark