Doc James Hammond
Very Strong User
Best idea yet.Take it to Sunset and put a for sale sign on it. Might fetch enough to cover gas...
Hank
Doc.
Best idea yet.Take it to Sunset and put a for sale sign on it. Might fetch enough to cover gas...
Hank
If it was to SoaringUSA don't use it on RCRCM products!Gift certificates are a very cool thing if you use them correctly. For example, recently my girlfriend gave me a very cool gift for our anniversary.
History:I need to start off by saying this is NOT a dig at the designer of the Strega. The Strega flew no worse than most other undersized tailed F3F racers of the time. In the intervening decades there has been a lot of development/understanding of the RC V-tail glider thanks to the men like Dr, Drela, Joe Wurts, Don Stackhouse. Most modern F3F racer are now coming in with a narrower V-tail junction angle (sub 100°), a lot more vertical side area, longer moment arms, all resulting in much more directional stability than the Strega.
The designer has complained that the tail decalage from the OEM (RCRCM) is not as designed. I have tried to modify the tail to meet the design criteria. I have to admit that I too found the OEM decalage less than optimal. But this had more to do with trim drag (needing down trim at my preferred balance point) rather than directional stability. I saw no real effect on the “ballooning” mentioned by the designer here. This looks to me to be a classic result of insufficient directional stability.
After the success of my modifications on the REDshift to the 96° V-tail I got to thinking, could this simple modification be applied to my Stregas?
This modification will be a target of opportunity as I’ll need to mix some catalyzed yellow paint to repair my Schwing Corsa 108. I really don’t think Strega can be made into a modern F3F racer. But it will be nice (I hope) to verify that the V-tail junction mod will be effective over more than just one design.
Now I have some concerns with bringing up the V-tail junction too much. Most theories that I’ve read don’t mention the efficiency losses in directional stability (and yaw dampening) as a result of narrowing the V- tail junction. You can think of the V-tail in yaw similar to a bi-plane set of wings, with much the same efficiency losses and interaction problems. This is even more acute with lower aspect ratio tails we (I) have on the Strega.
But as shown with the REDshift the added vertical area from the narrowing of the V-tail junction does add real world stability faster that the efficiency losses from the narrower junction angle (inter-plane interaction). With the REDshift I notice a significant improvement going from 104° to 100°. Going from 100° to 96° did not have near the effect on directional stability. I again think this is as a result of diminishing returns as a result of the afore mentioned efficientcy losses.
With Strega I’m going to try to bring the V-tail junction up to slightly under 100°. I will be using the Yellow Strega as for some unknown reason it generally doesn’t fly as well as the White and Red Strega.
Did you ever have the "privilege"of owning a Strega (flying your own ship)? If not that 34 sec time is real good for a borrowed ship!History:
As far as I have been able to ascertain, the Strega was "Gotten to" by an "unknown" German Gentleman (I know who he is) after I signed off on it and I had no idea that it might have been modified until people started to ask me why it would not turn properly and would shoot off into the wild blue yonder - If it didnt stall that is. Also why it would not fly straight and level without constant dabs of down or with a CG so far forward it turned into a wet sponge.
I did not actually examine a model until over a year after it came out as the test plane I was promised never came.
Examination results - Apart from the usual low standard of construction common to most RCRCM models:
*This is something to check on all Stregas as it only takes a hair dryer to fix - but don't leave it out ithe sun as the resin quality was inferior and highly heat sensitive so it will just "banana up" again.
- The aeroifoils "might" have been mine though I'm not sure as later they were claimed to have been designed by RCRCM ("RCRCM Special") so that's open.
- The wing and tail had been given an angle of attack of at least 2 degrees, which if in fact the airfoils were mine would effectively kill most of its turning ability and the straight line speed.
- On the fuselage of the one I looked at, it was *banana-shaped having been leaned up against a wall or something when it was still green out of the mould.
- The vee tail angle on the original design was 102 degrees and the same on the production model.
- The Vee tail area was the same as the orginal design.
Hey Blitz - even if you get a really well made version - if there are any, the basic model has a huge flaw in that RCRCM - unknown to me at the time - modified the incidence. There actually should be no incidence so the tailplanes need to be moved up at the front in order for it to have any chance flying well. Its a serious mod and if done wrong could be pretty catastrophic. You probably dont need that kind of hassle.Konrad or James Hammond...you guys still out there?
I'm going to purchase a Strega II .....glass/carbon version...
Anyone flown it or any impressions a out it?
Cheers!