oldtyme

OK guys............I've been building for a long time so I pretty much know what I'm going to do with the SIG 4* 40 I just got but I have a couple of questions and would like opinions.

The leading edge of the wing on this bird is not sheeted. Most all of the other builds I've done have sheeted wings or at a minimum a sheeted leading edge. It seems that a sheeted leading edge would be stronger and easier to repair. I'm arguing with myself if I want to alter the wing ribs and sheet the leading edge or just build it as designed.

Secondly, I've heard a lot about the landing gear on this bird and indeed the aluminum landing gear seem to be on the soft side hence I would expect they would bend in the event of something harder than a featherlite landing. I bought a set of Dubro fiber gear and they look really nice but they put the plane 1" higher than the stock gear. Do you think that that is a no-no or it won't make a difference.

Like I said all opinions welcome from experienced builders and ASAP would be appreciated because the wing is the first build.

Thanks in advance,
Andy

RCKen

My Feedback: (9)

I've had a few 4-Stars with hundreds of flights on them, and I've never had any problems with the stock landing gear. However, if you want to replace them an extra inch in height isn't going to make any difference in the way the plane flies.

Re-engineering the wing to include leading edge sheeting is unnecessary. The wing is designed so that the covering will give the wing the strength needed for flight. The 4-Star is a well proven design so trying to rework the wing really isn't needed. If you want to do it for the fun of the work there is no reason why you can't do it. But it's not needed as the wing build stock is more than strong enough to handle the rigours of flight.

Ken

oldtyme

Thanks Ken............I was just concerned with the attitude of the plane sitting on the ground and the start of the take-off roll because the added height would change the angle of attack until airborne.

RCKen

My Feedback: (9)

It will only change the angle of attack until you gain enough speed for the tail to lift up. Once the tail is off the ground the wing will level off to it's normal flying attitude no matter how high off the ground it is, and the plane will fly normally.

Ken

foodstick

Some people claim removing one wing bay on each wing is a nice improvement.. Seems to make it a bit more quick to roll without losing any floatiness...of course the 4star is famous for a long ground effect at landing.

I have heard some people swear you need to beef up the fuse right behind the wing saddle..I personally have never broke one there. But I have seen it done after a tumble !

Lets see I don't recall if the instructions show triangle stock at the fin stabilizer joint..but I'd install it.

Lots of people cut down that HUGE canopy

You can't hardly mess one up

RCKen

My Feedback: (9)

I can vouch for cutting the bay off the wing. In fact, on my 4-Star 120 I cut two bays off the wing tips and it really woke the plane up!!!!!!!

Ken

KitBuilder

I've seen the rear turtle deck thinly sheeted instead of the stringers which looks nice and I cut one bay and tear-dropped the wingtips on my .40 (RIP). I just reversedthe canopy and recut to match the fuse line.... looked much more sleek. I've got a 60 on order and can't wait..

noveldoc

My Feedback: (2)

I asked Bruce Tharpe the designer about the wing structure. He said use a decent iron on cover and this gives more than enough strength to the whole unit without the extra weight.

Tom

Gray Beard

My Feedback: (-1)

You can just use a taller tail wheel if your worried about the AOT. I have sheeted the wing once but it was just to keep people from grabbing it by the wing and breaking or poking fingers through. It really did nothing better then the stock wing. I have sheeted several of the turttle decks but it wasn't for strength, it was because when I have the planes in my cradle and I'm working on them I always seem to break a stringer or two. The wing bay thing, I don't often build the 40, it's been a while. I have built a ton of the 60s and until last summer I have always removed two wing bays to improove the roll rate, it works and the plane is still a floater. The last one I built was bone stock. It didn't have the best roll rate but it was perfect for the pilot I built it for. It's been quite a while sense I have built the 40 but I use the 60 as a teaching aid for people that want to learn to build kits. Nice plane and great learning tool.

ChuckW

I scratch built a sheeted wing for one and it worked great. What I did was cut new ribs that had their outline reduced by 1/16th". That way the addition of sheeting and cap strips didn't affect the overall size of the wing and it fit the fuselage good without any hassle.The wing was very stiff and it flew great. Was it necessary? Probably not but I like to do stuff just for the experience sometimes. I didn't have to deal with taking out any warps in the wing that I introduced with the covering though.

In the pics you will also see that I stick-built the tail. That was a mistake. It made an already nose-heavy airplane worse. My receiver battery was almost back by the tail to balance it. I should have just used the tail pieces supplied in the kit or made some new ones from sheet if I wanted a different shape.

I also reduced the dihedral. Another mistake. Bruce Tharpe put it there for a reason.

ARUP

I put a 'V' tail, slots and barn door ailerons on mine with reduced span and rib thickness and sheeted 'D' section like you are considering. It was a 'hoot' plus I like to 'change' things!

glowhead

Someone added 2 bays on their 4*40 on each side. The bays had a little more dihedral as the main wing... he learned on at as a trainer.
I built a wing and clipped two bays from each side. This REALLY wakes up the airplane now the wing is shorter than the fuse. I replaced the balsa sticks for spruce, not because of flying damage.. there is always someone that picks up the plane and breaks the forward stick with their thumb.

I love the sig family of planes. I train on sig senortias, Encourage the 4* or the mid* as their second.