Prism 3M sailplane - Looking for info

[aeajr]

Friends,

I just acquired a Prism 3M sailplane from a club member who no longer flies sailplanes. He did not have specs, plans or anything else. He has not flown it in years judging by the layer of dust on the tail. I am looking for any help I can get for sources of information.

My searches on this forum have not turned up much that is helpful.

The plane is a full house T-tail with plug in wings which appear to be obechi covered. White molded FG fuselage. I did see some references saying that it might have been made by Slegers International, but their web site is gone.

The plane seems to be in pretty good shape. Some repair work will be needed on one wing near the wing rod. I don't have wing rods, so any help on the specs for that would be appreciated as well. I just like to gather as much info on a plane before I start to work on it and set it up.

Thanks for any help you can provide.

[SR71]

Hi,
From your discription I believe that you may have a plane built by Ron Vann, wings, stab were built by him, and the fuse, and at on some of em were built by S. Hug. The plane was built in Windsor, CA. and when I was living in Navato, Ca went up there and picked "T" tailed prism w/RG 15 w/Titanium wing rod...Yes it flew real nice until I made a "pilot" error.....oh well....still have the wing rod though.....for your info the rod measures 8.5 inch long by 3/8" dia. ...

Wylie

[aeajr]

Wylie

Thanks for the wing rod specs. Every little bit helps.

And thanks for the background specs. That helps me further my research.

[SR71]

Boy! that was quick, if my memory serves me correctly the CG was under the wing rod, Its been some years since I had this acft. Ron V. was and is a building contractor and as far as I know he still in Windsor, CA. anohter source you might call or email "Seth" @ DSETH101@PROSETH.COM he used to work with R. Vann and I'm sure he can give you some skinny,,,,,if the above does not work, do a google on the Clearlake Modlers Club he is the current President and you can get a hold of him that way.....


Wylie

[Kestrel]

I am aware of a Prism that was built by Ron Vann and I think it was Steve Hug that built the fuse. I believe it was sold by NSP among others. I think that NSP has a few items available for sale. It was also available as a "V" or "T" tail. There is a local flyer that has one. It, or at least he flies it very well and has won many contests with it. It doesn't seem to be as good in a stiff breeze.

[aeajr]

Thanks guys. This is all very helpful stuff.

[Tony D.]

Slegers sold the Prism at one time.

I flew one of the 7037 ones for a bit. It is a nice flying ship.

The fuselage on the one I had was made by FuseWorks.

After I augered mine I cut the wing up to have a look. The spar was a piece of balsa that had some +/- 45 degree fibreglass bagged on it with a strip of carbon between the spar and the obechi sheeting.

I replaced the titanium wingrod with a steel one and there was less flex on launch.

Mine flew much better with ballast. If you have the 7037 wing try adding 8 ounces even in calm conditions and see what you think. Then try 12 ounces. Like other 7037 gliders I have flown I found the performance improved in all areas with the added weight.

Careful on launch when you are ballasted though.

Of course you might have the RG-15 version.


T.D.

[aeajr]

How do I tell which wing profile I have? is there a marking somewhere?

[Tony D.]

Here you go:

http://www.nasg.com/afdb/show-airfoil-e.phtml?id=1078

http://www.nasg.com/afdb/show-airfoil-e.phtml?id=1007


You can print these out and compare with the wing root.



T.D.

[aeajr]

Thanks!

I have the SD7037 foil.

Man, what a great community we have here!

Thanks everyone!

[chillybee]

Aeajr,

I just bought the 7037 Prism from RCU. How do you like the way your's flies? After reading about the titanium rod, I think I'll replace mine with CF to strengthen it up.

Chillybee

[aeajr]

Chillybee,

I have not flown my Prism yet. I had planned to get it in the air fairly quickly, but decided to focus on my Airtronics Legend for the rest of this season. The Prism will be a winter prep project. Needs some refurb work.

I have too many planes flying and enjoy each of them, but I am not spending enough time with any one to get really good with it.

I just flew the Legend in an Eastern Soaring League contest. Dead last but I finished and was much improved over my June showing.

When you get your prism in the air, I would like to hear your impressions.

[chillybee]

Aeajr,

I know what you mean by too many planes. I should be recieving the plane in about 2 weeks. The guy who's selling it is sending info on the cg and control throws. From what I've read, people say it flies quite well and actually likes more weight....which is something I'm not used to. Anyway, I'll see how it goes. Does your club have an aerotow each summer? If so, then I may have visited your glider field.

[aeajr]

Yes we do have an Aerotow each summer. In fact it will be next weekend this year. Field is in Syosset, on Long Island. The club is hte Long Island Silent Flyers. www.lisf.org . We also host two ESL events each year.

Send me a PM with your e-mail. I have the build instructions in a word document that was provided to me by the guy who wrote them. You might find them useful.

[georgeg]

Aeajr,

I just bought the 7037 Prism from RCU. How do you like the way your's flies? After reading about the titanium rod, I think I'll replace mine with CF to strengthen it up.

Chillybee

I flew an RG15 Prism for a couple of years and its a good model. The titanium rods were substituted for steel to reduce weight a bit while still having a rod that wouldn't take a set in the event of a dorked landing. I never found the flex on launch to be a problem. I don't think substituting a carbon rod in this size is a good idea. I don't think it will be strong enough. I still have a replacement Prism fuselage and a set of home bagged 7037 wings and tail to build up a new Prism one of these days.

[chillybee]

I flew my Prism last week on a nice sunny day. I was able set up the flap/elevator mixes and see how well it flew. The thing flies great and is very responsive to all of the controls. Even at very slow speeds, the ailerons are right on the mark. I even managed to get 500 foot starts with my hi-start after figuring out how to release the skinny fuselage. The only things I have left to do is to replace the wing servos with thin HS-125's and install higher capacity batteries...I plan on getting long flights with this ship.

[aeajr]

Friends,

I just acquired a Prism 3M sailplane from a club member who no longer flies sailplanes. He did not have specs, plans or anything else. He has not flown it in years judging by the layer of dust on the tail. I am looking for any help I can get for sources of information.

My searches on this forum have not turned up much that is helpful.

The plane is a full house T-tail with plug in wings which appear to be obechi covered. White molded FG fuselage. I did see some references saying that it might have been made by Slegers International, but their web site is gone.

The plane seems to be in pretty good shape. Some repair work will be needed on one wing near the wing rod. I don't have wing rods, so any help on the specs for that would be appreciated as well. I just like to gather as much info on a plane before I start to work on it and set it up.

Thanks for any help you can provide.

It has been about a year I posted this. I thought I would let you know I finally put the plane in the air. It flies like a dream. :p

I had it out for the first time yesterday. Took it around the field a couple
of times off an up-start. Launched well and balance was perfect.

However I have a new problem and thought you might offer some insight.

The wings seem to be Obechi over foam. If I understand the design, the
strength is in the wood/foam bond. It looks like the wood is cracking in many
places. The prior owner has put some 3/4 ounce cloth and epoxy at each crack to contain and support it. When I got the plane there were some cracked areas that had not been glassed. However I think there has also been some breakdown of the wood/foam bond over time. I glassed the cracked areas as the prior owner had done.

During my test flights I had a hard landing from about 10 feet. Stalled it and put the nose it. :( Pure pilot error.

Fuse is fine and one wing is fine but he other wing split along its length
about 1/2 of the way right on the wing rod tube, almost the full length of the
ailerons. Peeking inside it appears there is some kind of spar here.

I worked tite bond aliphatic glue into the crack all the way through, to fully
soak the foam, then worked it under the wood skin as deeply as I could, and
tightly taped the wing together and weighted it down with magazines and books while it sat in the foam core cases overnight. Looks like the shape is right but I am in doubt of the strength of the wing overall.

My plan is to completely glass it the length of the ailerons with either 2 oz
cloth or 3/4 oz cloth and finishing resin. that should establish a good skin.
I will glass the other wing in the same way to keep them uniform.

In this one flight session I have fallen in love with the plane but fear the
wings are not going to hold up to much. :confused:

I would appreciate your thoughts on this.