beachbrada

My Feedback: (17)

I have a Four Star .40 and want to know how many bays to clip off the wings. And how much bigger of a rudder do I need for knife-edging? And how will she fly with the wings clipped?

n19htmare

My Feedback: (1)

One rib is all you wanna clip off. Not sure on the rudder size though. I was going to do this mod along with Dual servo but meh, got lazy.

Wild Foamy

dual servos are good, and also flaps (cut the aileron about 70\30 with the 30 part being flaps).

one bay is all you need to clip off.

you can also cut out some balsa wingtips to make it look a bit more appealing

flyX

I never actaully clipped it a full bay. I took a total of 4" off of the .40 and 6" from the .60 ..oh will.
I just moved in the tips during building.

I lower the diehedral. If I lay oneside of the wing flat, there's 1/2" at the other wing tip.

For dual airleron for the .40 , I simply just mount 2 servos side by side at the center of the wing.

For the my rudder I like to make it look like the edge or extra. 1 1/4 on the bottom and 1 on top.
I also add a 1/2" on top for counter balance. You don't want to go too crazy, if you add to much
it'll fluttler. This is on the .60. For the .40 , 1" on the bottom. To hold a knifegde you fly a little bit faster.
I carve or sand flairing for the vertical stab accordingly.

I also alter vertical stab by add a rear post . This will lock everything in place so that the vertical
stab is just not sitting on the horizontal stab. Incase I nose over.

I also like to raise the height/angle of the rear deck a little bit. around 1/2 to 3/4. This will give
the model more profile and help knife edge.

It held a knifedge easily with only a .61 magnum.

I've hollowed the airlerons to reduce weight. I used a drimel but i think it would have been easier
if I just cut the airlerons into sticks then build airleron out of them. And have an option of extending
the airlerons a little bit.

I also build a frame out of berch sticks to re inforce right behide the wing mount former of the fuselage.
That the weakest piont..You never know if you have to dead stick and do a pan cake.

I don't glue the bottom piece in front of the landing gear, rather i make it into a hatch.

Of course I trim the canopy to save weight.lol I think it looks better if i paint it from the inside, plus
it assist in visiblity.

On the .40 I usually have to mount the battery pack in the cockpit to balance the model without adding lead.

I also like to install taller landing gears and wheel pants.
I opt to make the gear mount studry and use metal screws.

7.2 lb load with fuel, for the .60 . It flew like a dream. Still very gentle but you can toss it around on high rates.
I can do consecutive outside loops without any problems with the magmun.
The most consecutive rolls I can do is 5. That's pretty good. They're not super fast rolls but the clipped wing helped.

It torque roll easily with a break in prop. That's how my instuctor broke it in or test flew it for me.lol Almost everyone had a chance to fly it.
They all like it.

jetmech05

the stock 4 star tends to float...if you remove a bay on each wing it will reduce the float some......I'd add winglets pointing up...it's easy just mark the shape of the last rib on plywood and draw the winglet in, cut, glue, and cover. when I've made them I've used a paper template ro ensure both side are the same....lastly the canopy on a four star is hideious...If I do another one I'll make it an open canopy

DaveB

Replace the stock tail wheel with a Sullivan.

DaveB

Gray Beard

My Feedback: (-1)

Flaps on A 4*?????
Just covering A 60 right now, other then the two aileron servos there isn't much difference between the two kits other then size.
The LG block is A weak spot so you should reinforce that. I clipped the wing one bay on each side and added I think 1 1/2 inch to the rudder. I discovered one of my 60 size Extra canopys fit the plane very well. And A good after market tail wheel was called for.
That's all I did to this plane because it's my young students planes and it's time to get it finished. A lot of people use 1/64 ply and cover the turttle deck. I have seen but not used one of the fiber glass cowls, that really makes it pop.
I just happened to have some good landing gear from my last OOPS and installed that.
It's A great little plane and A fun build, it lends itself to bashing so let your own mind go wild on it.
If you install the two aileron servos and have A good radio you can add flaperons or spoilerons then mix into your elevator or throttle just for some fun. This plane is such A floater flaps aren't much fun but the spoilerons can be A ball!!

beachbrada

My Feedback: (17)

To make your Rudder bigger did you just cut out a whole new rudder?

flyX

You can do it either way. either add a piece or build a new one.

It'll look cleaner if you build a new one or just cut the old rudder into sticks.

The .60 wood is pretty thick. I opt to rebuild it stick like to save weight.
Plus the stock rear conners are rounded.

ChuckW

I saw your other post about the wing repair so this would be a perfect time to clip the wing by one bay. You'll get a nice roll rate with very little noticeable effect on the flight characteristics. It will still float like a trainer on landing. You could also add some sort of wing tip to dress it up.

I'd leave the dihedral alone. I tried flattening a wing on one and it just made for a funny handling plane. I think Bruce Tharpe knew what he was doing when he designed the wing.

The dual servos are fine but absolutely not necessary. I wouldn't bother with them unless it made your repairs easier.

I would not bother with flaps. It's just extra work and extra weight for a plane that doesn't need flaps.

You can enlarge the rudder some but that's not the only thing that affects knife-edge flight. Maybe I am wrong but I figure a plane needs good side area to generate little lift while in knife edge. Giant rudders are great for 3D planes (which the 4* is not) because they need to vector prop thrust to maneuver at slow speeds. That's just my opinion anyhow. A little more rudder won't hurt though.

Here's a picture of a 4-star that I did a few modification to:

beachbrada

My Feedback: (17)

Thats a nice looking plane. My left wing panel doesnt have a aileron due to damage so how can I aquire a new one, will I have to make one or do you think I could go through sig?

bingo field

You should be able to buy aileron stock at the LHS, or you can order it through Tower, or some of the other places that sell balsa. Just measure the old one, and buy one that size, or the next size up and shape it accordingly.

flyX

You can get airlerons at the hobby shop, but they won't be tappered like the 4* star.
You can build it out of sticks.

WMB

My Feedback: (1)

The 4*40 will knife edge with enough motor, but adding a little to the rudder would be a good idea.
I used the Sullivan Golden rods- the grow and shrink with the temp. Replaced with the carbon rods- mucho better! No trim changes with temp.
Dual aileron servos.
sullivan tail wheel bracket.
Keep it light!
forget the flaps.
Fun to fly when overpowered or under powered. great plane- keep it light! Mine is now 4lb 10oz, but it can do better.

ChuckW

Sig service is great. I imagine they can sell you a new set of ailerons. They are just 1/4" balsa though so it might be easier to by some 1/4" sheet and cut a new one.

I would also avoid building the tail from sticks. There is nothing wrong with that building technique but mine ended up being too nose heavy when I tried it. The solid balsa tail pieces would have added a little weight and made the plane easier to balance.

Here is picture before covering. Again, half of what I did was unnecessary and/or didn't provide much benefit. I just like to mess with things.