Hay Chris. Here is some first hand information on DHL and V-Tails. I do not think that it is a problem with his incidence. I had a Simply the Best Fuselage and was having the same problem and what I did to decrease this problem was to program in less down on the V-Tail. In other words, if you are turning right, the right side is down and the left side is up. Decrease the amount of down, because as the plane starts to turn right the down side elevator makes the plane dive. This causes some real interesting looking launches. Hope this helps. -- Larry Pettyjohn | [EMAIL PROTECTED] | | http://home.earthlink.net/~lpettyjohn/ccsctimes.htm ScrollSander wrote: > > Hi Jim, > > Having just come back for the IHLGF in Poway I know what you might be going > through. The following is my guess as to your issue, that is if nobody else > has answered. > > First of all, since you are using a poly and a V-tail, I would take out any > offset during your launch. Then I might think that you have the incidence > set wrong, that is too much up. Take out noseweight and decrease incidence. > I do not know which way the plane is rolling however I would venture to say > that it is rolling left if you are throwing right handed holding the left > wingtip. > > Now the theory for the glider guys. > > 1) Your V-tail is acting as a propeller rather than a controlling factor > for the wing when the plane is going fast but still in your hand. Take a > look at the V-tail from the back end. Apply right rudder. I would expect > the left elevon to go up, the right to go down. If you look at each surface > you will see that the elevons if the fuselage is kept in a straight line > would force a twist to the left. Think of them as ailerons rather than > elevons at the time of release. Then at the time of release, once you start > turning left, the elevator becomes the truning surface and with more > incidence your get even more added force rolling the plane to the left. > > 2) Normal DLG have a sub rudder. This is so that the upper rudder twists > the plane left, the lower rudder twists the plane right and then they > balance. If the plane rolls over then the elevator again comes into play. > > Now how to avoid the turning with the v-tail? I would try to relase the > plane with your arm extended further out. Release it earlier then expected > as you could be pulling the plane into the left hand turn. It is not until > the wing is flying and working that the polyhedral forces come into play. > > FYI, I am preparing a CD with pictures of alot of planes form the IHLGF, > with some descriptions. It will be avaialbe for a small cost, but will have > alot of info. Right now I have all the pictures edited and the web pages > are being build. > > If you or any body wants one, let me know and I will inform you of the costs > when available. > > Good luck. I hope this helped. > > Chris > > ----- Original Message ----- > From: "Jim Crook" <[EMAIL PROTECTED]> > To: "RCSE" <[EMAIL PROTECTED]> > Sent: Tuesday, June 19, 2001 1:52 PM > Subject: [RCSE] DHLG Launching problems > > > I have a Poly V-Tail HLG of my own design. It was designed for the > javelin > > launch. It launches (javelin) and flies fine. Recently I have tried a > few > > experimental side-arm type launches "at low power". By low power I simply > > mean that I do not rotate fast or try to generate true launch speeds (I > > don't think the plane will take it). I am trying these test launches to > get > > a feel for the new launching technique before I build (or buy) a DHLG > ship. > > My problem is that on about 1 of every 5 launches the plane rolls over on > > launch. No amount of pre-set rudder seems to correct the problem or > reduce > > its frequency. Living in Montana has some advantages - being near people > > who fly sailplanes is not one of them! Any ideas? Suggestions? > > > > Jim Crook > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" > and "unsubscribe" requests to [EMAIL PROTECTED] > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and >"unsubscribe" requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
