I recently picked up a Sapphire ARC on Ebay. Looks to be a slightly larger Joker with more frontal area. Anyone have any experience with the ARC version? I am going to use it as a practice plane, and as I have access to Magnum engines, I am planning on putting a Magnum 1.20 TWO stroke in the nose. Your comments would be most appreciated.
Regards,
Mike

I think I remember this one - a Saphir II. If it's the Saphir II, it's designed for the early 1.20 4 stroke engines and has a larger wing than the Saphir (60). I built a Saphir (60) ARC recently and put a YS .60 LSRE on it. A 2 stroke engine (esp. a 1.20) may cause some pipe fit problems, as it goes under the wing and you have to cut out some of the wing skin, foam, and even part of the spars to keep it from sticking out too far. My plans had pics of a very small 4 stroke pipe, with just a little of the underside cut out. I cut a lot out and still had a plenty of pipe sticking out of the bellypan.

Another thing worth considering is the weight of the engine. If you add more up front than the plane was designed for, you may have to add weight to the tail to balance things, and the wing loading may go up. I was able to get the fuel tank near the CG by cutting into the canopy, making a cradle for it inside, and then painting the canopy to hide it. I sold the plane before I flew it. If I can find an pic of it, I'll send you one.

Good luck

The fuel tank was placed by cutting into the cockpit (not canopy), and the painted canopy hid it. Also, I wanted to add that I didn't like the retract installation method. I had one like this on an Escape, and the gear pulled out of the wing pretty easily. My next plane was a Boxer 60, which used a false rib under the wing skin and it worked great. Because the skins are already on the Saphir, I drilled the holes for the dowels with a sharpened copper tube to get a good snug fit, and then used ProBond glue everywhere wood touched foam, after wetting it. The plane hasn't flown yet, so I don't know how this worked, but it was the best I could come up with.

Yes, this is the Sapphire II. Hence the reason for putting the 1.20 TWO stroke in it. The Magnum 1.20 2 stroke only weighs 25oz., certainly no heavier than just about any four stroke 1.20, and probably lighter. I will consider moving the tank back when I get the kit in my hands.

Hi Mike,
i've built and flown the Saphir (.60 size) and it flew fine with an OS .61RF-ABC-P (If I'd had a Hanno special I'm sure it would have had more vertical!!). I have the Saphir II 4-T kit. It was designed around the original YS 1.20SF. 70" long and about 950"sq wing (mine is still in the box).
I saw Wolfgang fly the original Saphir (.60size) modified to accomodate the YS 1.20 at the 1989 World Championships. It was a rocket - it appeared to acclerate in the verticals; power was not an issue! Ironically, Tony Frakowiak flew the Fyg Leaf biplane powered with a YS .61LS at the same contest and it was the slowest airplane there. Both pilots flew well, but the difference in maneuver size was amazing!
One last tip, if you use retracts, make sure the retract plates are well anchored in the wing - to something other than just the foam! I made plywood plates running vertically from the top wing sheeting to the bottom and glued the LG plates to them.
Happy flying - love those funky wing/stab tips!
-Will B

Flywilly, good idea with the retract plates - sorry I didn't think of it with mine (oh, well). Sounds like the next best thing to having a false rib.

Bill

Hmmm, the ARC version I have is 74" in the wing. Any thoughts on how the 1.20 two stroke will handle it?

Hello
Do use the ply plates to stiffen the gear plate, otherwise itīll broke easily, plus, be carefull with incidence, mine came with the stab cut overly done and wing craddle with 4°+ incidence...
to fit the cowl properly i had to attach it with masking tape and with a heat gun, deform it permanently.
you will love it flying!
good luck / fred

Yeah, False ribs would be perfect, but hard to do in an ARC. Can be done, though: cut the slots through the bottom sheeting down (up??) to the top sheeting. The hard part is making the template - I just made a 1/2 template using the exposed bottom, then used it to make a ful sized cardboard template. I think going spanwse is easier and seemed to work fine for me.
The 1.20 2-stroke should be plentyofpower!
-Will