I in the process of assembling my Kadet Senior ARF. I'm at the point of mounting the cowl, and I have the hole all cut out for the engine and muffler. The firewall on the plane is built at an angle so the front of the engine points down when mounted on the engine mounts. The problem is that when I try to put the cowl on, in order to get it over the crank shaft, I have to point the nose of the cowl down so far that it looks ridiculous. Plus the top edge of the spinner still rubs on the cowl. The book says to mount the engine with the drive washer 4 1/4" from the fire wall. I even went a little extra and mounted it 4 3/8" so I would have plenty of clearance.

Well that's the problem
Here's the question:
1. Is the engine suppose/need to be pointed down this much?
2. If not, can I shim the bottom bolts between the engine mount and fire wall to correct this?

Here is a picture of the engine mounted. Hopefuly you can see how much it's pointed down

Here's a picture of the plane with the cowl put in place. You can see how much it needs to point down in order to clear the prop shaft.

Please, any suggestions??

It does look like to much down thrust in the picture. Normally down thrust runs from 1 to 3 degrees with 2 degrees suggested for starters on most of my aircraft. Since this is a new ARF on the market I would suggest you contact SIG either on their web site or by phone. Maybe this is what they intended then again you know how new ARF's can be with quality problems, not trying to scare you but I would contact Sig and send them a set of the pictures you have posted here.

Good luck

Hummmm
ill have to look at my sig but i am not ready to mount the motor..
please let us know what sig tells you

That downthrust looks excessive. I would half it and if possible mount the engine inverted. You can actually compensate for less downthrust by making your plane slightly nose heavy.The Senior Cadet is just about the worlds easiest trainer. Very very forgiving.
It also flies much better (tho less stable) with only half the dihedral. You might want to buy a wing kit (from the regular kit) and build it with less dihedral

Don't worry about the down angle. It's like that to compensate for the huge amount of lift the wing generates.

It may be true that the plane needs this much downthrust, but the way the cowl has to be mounted still looks funny. Something just ain't right here! I don't recall having such a problem with the World Models Frontier Senior which I constructed a year or so ago.

Please keep us posted as I have the ARF Kadet Senior in the box under my bench. Like the WM Frontier Senior so well that I just had to try the Sig offering.

Sam

I have owned the WM Frontier and seen many Sigs over the years and the Sigs do have more down thrust than the WMs--Does it make a difference--I don't know but I remember thinking it looked like a lot and that was 12 years ago--most things I forget in 12 minutes.

hey guys if you look on page 26 of the owners manual the drawing shows the engine with quite a bit of down thrust but they don't give a number.. but the drawing does make it lokk like a lot.

So far the only info I've been able to get from Sig is the kit is designed with 6deg of downthrust, and it needs that much in order to be able to land without difficulty. If that's what the plane needs, I'm fine with that, I just can't figure out how to make the cowl fit and look decent.

Hanger Rat, what will the effects be if I mount the engine inverted?

What if you just trim the BACK edge of the cowl to be perpendicular to the fuselage thrust line? It would then "appear" better.

If you are using a powerfull .46, and it looks as though you are. You will probably need more downthrust than that built into the firewall. I have one built from a kit with the TT .46 it needed about three washers under the back of the engine to run right. With a K&B .40 it was alright without the washers. IMO the Thundertiger was way too much power. The K&B is a bit underpowered on a hot day, a modern 40 (not LA or GP) should be about right.

Suggest you fly it without the cowl and adjust the downthrust before correcting the fit. Who knows you may need to add a few washers to the front of the engine.

Another alternative is to mount the engine higher. This has a similar effect to downthrust and may make the cowl fit better, if the front of the engine isn't too high.

I have a Kadet Senior kit (not ARF) still NIB, and I checked the plans. Yes, the down thrust on the ARF looks to be about the same as shown on the kit plan.

I wouldn't worry about the downthrust being excessive. The big flat bottom wing needs it. However, that down-pointing cowl does look funky though. I have seen several Kadet seniors built from kits, and even though most of them don't have a separate cowl, they all have noses that point straight forward. My suggestion is maybe to enlarge the prop shaft hole on the cowl so that it can be mounted more or less straight with the fuse.

Rub,
Might want to make sure the motor mount is on right side up. Looks to me that motor sits too low. Turn the motor mount around and it'll raise the motor so the cowling will fit.
Mikee

Thanks Mikee and everyone else, yes I feel kind of dumb, but your right on the money. I just received an email from technical support at Sig saying that he saw the pictures on here and noticed that I had installed the motor mounts up side down. So to all of you that mentioned concerns about your unbuilt kit, have no worries, correcting my mistake should correct my problem, and I would like to say that I have been very impressed with the rest of the kit. Also a big thanks to Scott Christensen of SIG Mfg. for not only taking the time to look through the forums but to also personally email me to help solve my problem.

All is well. I turned the motor mounts over and now the cowl lines up very nice. Again thanks to everyone for your help

Okay, I guess it'll work alright. I looked at the picture again and to me the motor mount looks to be installed correctly. I don't know about those included with the ARF, but with most motor mounts you install the engine so that the thrust line goes through the center of the mount. This is so that you can rotate the engine 90 and 180 degs and still maintain the same thrust line. plus the hole on the side of the motor mount facing the camera looks like it's for the nose gear to go through if the engine were mounted sideways. That hole then should be centered with the engine, as it is shown in the picture.

That said, I don't think there's anything wrong with mounting the engine on the "wrong side" of the mount, if it suits the application better. I've dont so in the past with no problem.

The motor mount in the photo is installed correctly

I guess that depends on who you talk to on it being installed correctly. Obviously it wasn't cause the motor did not line up like it was suppose too. The problem has been solved with the most simplest solution. The motor mount in this case was installed incorrectly. RTN9105 installed it the correct way and problem solved. This doen't need to be debated as most motor mounts can and will be mounted in different ways whether it's right or not. 'nough said
Mikee

You don't have a problem. The Pic shows the fuselage pointing downward, making the downthrust appear to be excessive. Look at the top of the Fuse, and the lateral balsa seam under the white and red Monocote. It's not level. That seam is in essence your thrust line, (roughly,) and you need that much downthrust if you are using a .46.

You'll be OK; go fly the thing !

Mine checks out at 6 degrees. I am sure that this amount keeps it from climbing excessively and helps the plane land so very well. However, I have been flying off some rough grass and the plane seems glued to it on take off. Never have I had such a long take off roll. However, I must say that it looks realistic doing so. Once in the air I cruise at 1/4 throttle with my Mag. .61FS. I imagine that the down thrust is what is keeping it on the ground so long. Not a problem though, as I dislike a take off with an airplane that looks like the pilot is trying to act like it is a heli!

hey old dutch how does you sr fly once it breaks ground?

As to the actual flight, you will find that it handles like an ideal trainer should. On the initial flight I needed 2 clicks of left aileron to get it straight, level, and hands off. It can be slowed up and you can chug around the field and just admire it. I was pleased that I could advance the throttle considerably without it nosing up like a lot of other flat bottom winged planes do. I haven't fully broken the engine in, flight wise, so I haven't gotten too frisky with it yet. However, I did some big loops that looked real good (I may increase the elevator travel) and to my surprise I could get rolls that actually looked very good. (used just a tad of down ele. on the inverted part of the loop. Landings can be as slow as a walk speed or whatever you wish. In thinking back on my long take off roll, I now realize that I was going a bit downhill, I was dragging tall grass under the belly, and my nose gear may need to be dropped down a bit. On good grass, and a better angle of attack, I think that it will take off much better. The engine actually pulled it quite fast on the ground (ground handling was great) and I think that a more positive angle of attack for the wing is all that I need. I have built and flown a lot of planes, some bigger, some smaller, some a lot faster. None more fun. Cheers!

old dutch

did you glue your wings toggether? and will it roll

I did not glue the wing sections together. I did glue the round connecting rod to one end, so as not to lose it. The main aluminum rectangular connector is just pushed into one end and carried there. It fits snuggly, so I did not glue it. All in all it works out just fine in two pieces. A word of caution on the wing. Be very careful in handling it during installation of servos, etc. The large ribs are made of the lightest, softess, balsa that I have every seen. (did I say fragile?) As for rolling the plane, yes it does, and does so surprisingly well. This plane is far from my first, but it is my recommendation as a first plane for anyone just getting into flying. Large enough to stay oriented with, handles responsively yet not twitchy, can be flown very slowly, handles a decent amount of wind, and landings .....well it just doesn't get any easier. A word about the all important landing gear. The gear legs are 3/16 in. strong, and are in two pieces for good torsion effect. Wheels are large and light. Mains are 3 3/4 in and nose wheel is 3 1/4 in. Stance is 17 in. I'll bet that whoever came up with that combo is an experienced RC flyer! Go get one of these. Your biggest decision now is the color combo!!!!