I have an oportunity to finish building (covering only as I understand it) a hand -me-down Sig Riser 100. Anyone have any comments on this sailplane. I have an OLY 2 and am assuming it is simular with respect to strength and performance. Any mods on this model that would be recommended? Thanks very much.
Cheers
Rob

I have no direct experience with the Sig Riser 100.

The specifications say it uses a modified Eppler 205 airfoil. If the modification didn't remove the Phillips entry by making the bottom of the airfoil flat all the way from leading to trailing edge and if the wing structure is sheeted top and bottom ahead of the spar, then the Sig Riser will have better wind penetration ability than the Olympic II. A sheeted D-tube will give the wing much needed torsional rigidity. The bolt on wing option will reduce parasitic drag further improving wind penetration, if the Riser was built with it.

To test the wing for the required strength, support the wing between two chair backs or tables spaced 42 inches apart. Apply 12 pounds of weight to the center of the wing. If it survives, it will be strong enough to withstand high start launches or moderate winch launches in winds up to about 12 MPH. If it doesn't survive then it wasn't worth covering, in my opinion.

Thinking back 20+ years I would say that the Oly 2 and the Riser were similar in performance. Perhaps the Oly 2 had a slight edge.

If the plane is free, I would slap some 1/4" carbon tape on the spars, check the shear webs, cover it and use it for a back-up glider.

I always crash when I'm down to one plane.

Sierra Gold

The Riser and Oly look msimilar to one another but are actually quite different both structurally and aerodynamically. The Riser has a beefier wing with fully sheeted L.E., so assuming it's built correctly it will take a harder launch than an Oly 2. (Still weak by today's standards though.)

The airfoil ("modified" Eppler 205) has a pronounced Phillip's entry, so the ship is a lot speedier than the Oly as well.

It's more like a Sagitta wing on an Oly 2 fuse.

Cover it, fly it, give us a report!

Cheers,
Dave

i only ever flew the 2 metre riser and i first assumed it would be a step better than the gentle lady but i found it to be quite good ,dont know if its the same wing as the 100 inch riser but i thought mine was worth the build,,allthough i would ask your self why you need two 100 inch floaters??

just jokin!!! helping you get primed for the wife when she asks!

build it maybe add e-power????



viti

I have a Riser 100 in my basement and I can assure you that it does not have a sheeted wing (perhaps the riser 2M does, I don't know). One problem with the design is the wide rib spacing and the resulting covering sag between the ribs, especially forward of the spar. Also, take it easy on the winch unless you beef-up the spar with carbon and use thick shear webs. Still a fun plane to fly, my best flight was about 45 minutes. However, it can't hold a candle to my Laser Arts Majestic.

Thanks for all the input guys. I'll have to see what state the model is in. If I'm lucky, maybe the wing has been sheeted,if not, that will have to be taken care of. May be a little tricky accurately trimming the ribs to accept the sheeting with it already built up. Full "D" tube sounds good. I'll be sure to ensure the webbing in done properly as well. When I'm satified with the structure I'll get the 12 pound (I'll get the calculator for Kg...Canada Eh!) weight out and do a strength test before covering.
Probably would be a good choice for electric as well..I understand it has a lot of room up front. Got me thinking...Might need some expensive stuff up front on this size of bird...just don't tell my wife!
Cheers,
Rob

I stand corrected on the L.E. sheeting, though I would have sworn the one I saw had it. Either the builder modified it, or I just remember it wrong. It was a few years ago...

Cheers,
Dave

[it has a lot of room up front. Got me thinking...Might need some expensive stuff up front on this size of bird...just don't tell my wife!
Cheers,
Rob [/B][/QUOTE]

if you do think about e-power that a perfect glider for a cheap brushed motor from the buggy hobby,i can give you some great advise to e-power that bird well for about 200 bucks cdn,ive done it myself on a similiar 100 glider,lots of room makes for a cheap power system

im in canada too ,in fact im in southern ontario ,pm me if you like



viti

I have a friend who is hi-tech but his son flys a 100 (I was flying a 2m Riser so we were soul mates). This 12 year old held his own in our club contests and had excellent flights and landings. Young eyes didn't hurt this I'm sure. Anyway, his was built stock per the plans without any tweaking. He always checked the trim carefully before launching (or got scolded by dad I'm sure) and really seemed to enjoy himself which is the real reason we like this activity isn't it?

Keep looking up!

If the ribs are that far apart (and I seem to recall that they are) you can hot rod the model with turbulator spars to support the covering that much better. It can be done very easily too.

Use a yardstick to mark off some spar lines and use a bundle of hacksaw blades CA'd together to act as a "file" to cut the slots. Or you can get a small square coarse file and grind the sides smooth. The turbulators should be about 1/8 sq but cut them wide enough so they are a snug fit into the slots.

Add 2 or 3 spars in front of the main spar and one behind on the upper surface. Put the first about 1/2 inch behind the leading edge and the others space about 5/8 to 3/4 up to the main spar. Add the covering support spar behind the main spar at about 3/4 to 1 inch. This last one is quite important as there's a LOT of covering sag behind the spar and it'll definetley affect the stall. The extra spar will help avoid this. If there's quite a bit of curve in the Phillips area on the lower leading edge then I'd add a last support spar about 3/8 to 1/2 inch behind the leading edge down there as well.

And definetley cap the spars with carbon as suggested by the others. Fuzz up the glueing side but don't cut the fibers too badly. You just need to take off the shine for the epoxy to get a better bite.

All this won't be quite as good as the D box and only adds a little to the structural stiffness but it'll give the aerodynamics quite a boost and perhaps make the Riser into a better performer in the wind. Modify it for bolt on wings to get rid of the rubber band and dowel drag too.

Another hot rod option would be to make up "sheeting" from 1 oz glass cloth. This won't add any meaningfull thickness to the overall airfoil but it would require that you trim back the leading edge and add a new one to ensure the proper shape on the critical leading edge area. It's a LOT more work though and the Riser may not be worth the effort. I'll add more detail if you are interested but it's a lot of steps.

Still haven't seen the airframe yet..I'll probably pick it up this week...Have my fingers crossed that it was well built so far..
I have not yet worked with carbon fiber. Will be building a BOT this winter as well, and am planning to beef up the wings as well... Time to figure it out! What is the best form to buy it in for use on spars? Any suggestions for a good place to buy carbon fiber in Canada? Toronto area?
Thanks for all the suggestions. Much appreciated.
Cheers,
Rob

did you get a chance to look at the airframe , i just received my riser 100 kit and have started a build , and it looks like a sure winner to me. just make sure that you reinforce the fuselage near the le of the wing , other than that it should be a great flyer.

cheers
doug

Hi Doug,
Yes I did get the airframe. The Riser sat around for the better part of the year as I had some other stuff on the go. Made a decision that I just wasn't going to get to it for a while. Since it was passed on to me to finish I thought the only fair thing to do would be to pass it on to another club member who wanted a project.
Didn't take long to find a home for it. Have not heard how the hand me down Riser is. Hopefully I'll see it flying this summer. I'll let u know.
Cheers,
Rob