Shrike .10-OS .25 vrdf project
08-23-2009, 03:49 PM
#26
Thread Starter
My Feedback: (11)
Join Date: Dec 2003
Location: RR#7 Aylmer,
ON, CANADA
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
I dicided to put the elevator servo in the tail, because I figured it would hide the linkage a little more from the exhaust goo and I had room to move the battery ahead a little if req'd, with the extra weight shifted to the tail, here's some more pics.
08-23-2009, 09:59 PM
#28
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: smoknrv4
I probaly overkilled the linkage, but its what was handy.
I probaly overkilled the linkage, but its what was handy.
MJD
08-23-2009, 11:29 PM
#30
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
Oh no, look.. he's really upset this time. Such an emotional tightrope we walk around here.
Don't feel too bad CP - SmokinSumptin' made those hisself, and even gave me some to pretty up my models.
I sent you a pilot figurine, where's that?
MJD
Don't feel too bad CP - SmokinSumptin' made those hisself, and even gave me some to pretty up my models.
I sent you a pilot figurine, where's that?
MJD
08-24-2009, 07:50 AM
#32
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: combatpigg
I thought it was a piece of candy and ate it
I thought it was a piece of candy and ate it
MJD
08-24-2009, 04:32 PM
#33
Thread Starter
My Feedback: (11)
Join Date: Dec 2003
Location: RR#7 Aylmer,
ON, CANADA
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
Hopen to get out this week to maiden, I'm a little concerned about the weight, it does have a 6 Volt pack, might not be as fast as my Demon but it'll sound way cooler[8D], we'll see, should be a hoot though.
BTW... those decals are no longer in production, Mike and myself are the only ones in possession of these pieces of art, might want to hold onto them Mike, they might be worth something someday.[sm=bananahead.gif]
BTW... those decals are no longer in production, Mike and myself are the only ones in possession of these pieces of art, might want to hold onto them Mike, they might be worth something someday.[sm=bananahead.gif]
08-24-2009, 06:23 PM
#34
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: smoknrv4
BTW... those decals are no longer in production, Mike and myself are the only ones in possession of these pieces of art, might want to hold onto them Mike, they might be worth something someday.[sm=bananahead.gif]
BTW... those decals are no longer in production, Mike and myself are the only ones in possession of these pieces of art, might want to hold onto them Mike, they might be worth something someday.[sm=bananahead.gif]
MJD
08-26-2009, 07:41 PM
#37
Thread Starter
My Feedback: (11)
Join Date: Dec 2003
Location: RR#7 Aylmer,
ON, CANADA
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
Well I rushed home from work today, loaded up the car with my SD and the Shrike for some flying, I got to the field, and set up. I fueled up the Shrike, and the engine squealed to life, I set the needle to peak 21900, then back off to about 21 000, shut the engine off and re-fueled.
Then I set it aside, fueled up the Demon and my Control line flying buddy Ken launched it for me, had a great flight, but the engine ran a little rich for my liking.
Set the Demon aside, and set up the Shrike on my stand for the Maiden!
Fire it up and after a few more glances at the control surfaces, full throttle, Ken tossed it the air for me, Sweeeeet it went straight into a smooth flight path and climbed out, I only had to put 3 clicks down for elevator and it flew awesome, no left roll on launch either it launched really nice, flying it feels just like the Demon, and I think it was a little slower though, its hard to tell, but it sounded cool as it squealed by, rolls are quick, especially on high rates, and the colour scheme was awesome for orientation, had about a 5 min flight and brought her in, she landed smoothly down the grass strip like it was on a skating rink, a fairly uneventful flight, WHEW, got the maiden out of the way, and it was good, I love that feeling.
I put another flight on it later after a couple more flights with the Demon., and again, nice flight, lots of fun to fly, I leaned it out a little more for the second flight though and that was more like it, for speed.
All in all a good night of flying, I love those nights.
Then I set it aside, fueled up the Demon and my Control line flying buddy Ken launched it for me, had a great flight, but the engine ran a little rich for my liking.
Set the Demon aside, and set up the Shrike on my stand for the Maiden!
Fire it up and after a few more glances at the control surfaces, full throttle, Ken tossed it the air for me, Sweeeeet it went straight into a smooth flight path and climbed out, I only had to put 3 clicks down for elevator and it flew awesome, no left roll on launch either it launched really nice, flying it feels just like the Demon, and I think it was a little slower though, its hard to tell, but it sounded cool as it squealed by, rolls are quick, especially on high rates, and the colour scheme was awesome for orientation, had about a 5 min flight and brought her in, she landed smoothly down the grass strip like it was on a skating rink, a fairly uneventful flight, WHEW, got the maiden out of the way, and it was good, I love that feeling.
I put another flight on it later after a couple more flights with the Demon., and again, nice flight, lots of fun to fly, I leaned it out a little more for the second flight though and that was more like it, for speed.
All in all a good night of flying, I love those nights.
08-27-2009, 11:52 AM
#41
RE: Shrike .10-OS .25 vrdf project
I've seen these engines NIB for sale and didn't know enough about them to bid on. I think you find a lot of these NIB because the intended fan project turns out to be too much for the guy with big ideas.
So I guess your need for speed has been pretty well met for now?
So I guess your need for speed has been pretty well met for now?
08-27-2009, 01:46 PM
#42
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: combatpigg
So I guess your need for speed has been pretty well met for now?
So I guess your need for speed has been pretty well met for now?
MJD
08-27-2009, 05:21 PM
#43
Thread Starter
My Feedback: (11)
Join Date: Dec 2003
Location: RR#7 Aylmer,
ON, CANADA
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
MJD is right about that, it was too routine, not at all what I was hoping for but still fun, I think I might try a 7-4 prop to see what happens, the RPMs didnt hit where they should have, that engine should be able to do more, if can do 25K in a fan unit.
08-27-2009, 07:07 PM
#44
Senior Member
My Feedback: (44)
Join Date: Feb 2008
Location: kuna,
ID
Posts: 896
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
try some 20-25 percent nitro on the 25 df motor it may really wake it up, i use a 20C carb on my small os engines...40 size perry on my 3.5 k&b........
08-27-2009, 07:21 PM
#45
RE: Shrike .10-OS .25 vrdf project
I'm pretty sure a 4 pitch prop needs to turn about 30,000 rpm before you'll have anything to get happy about. I'm guessing the .25 needs to be in a smaller and less drag plane than the Shrike, something more like a hotliner. I would think then a 7x7 prop would really be able to get it done.
08-27-2009, 08:01 PM
#47
My Feedback: (1)
Join Date: May 2003
Location: Orangeville, ON, CANADA
Posts: 8,658
Likes: 0
Received 2 Likes
on
2 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: smoknrv4
MJD is right about that, it was too routine, not at all what I was hoping for but still fun, I think I might try a 7-4 prop to see what happens, the RPMs didnt hit where they should have, that engine should be able to do more, if can do 25K in a fan unit.
MJD is right about that, it was too routine, not at all what I was hoping for but still fun, I think I might try a 7-4 prop to see what happens, the RPMs didnt hit where they should have, that engine should be able to do more, if can do 25K in a fan unit.
MJD
08-27-2009, 10:41 PM
#49
Senior Member
Join Date: Oct 2006
Location: Düren, GERMANY
Posts: 296
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
ORIGINAL: smoknrv4
MJD is right about that, it was too routine, not at all what I was hoping for but still fun
MJD is right about that, it was too routine, not at all what I was hoping for but still fun
The recommended way to go fast should always be taking an airframe design that already comes with very promising speed potential.
Another “speed secret“ when dealing with high-timed engines like the OS .25 VR-DF of course is to effectively make use of very small diameter props (plus high prop pitches if possible). This again demands a very low drag airframe.
So in case of the OS .25 VR-DF engine the Shrike simply is much too bulky.
A very suitable speed airframe for your OS .25 ducted fan engine is the Me-163 Komet by Topp-Rippin for example.
http://www.rcgroups.com/forums/showt...0#post12735390
http://www.rcuniverse.com/forum/fb.asp?m=8985804
Set up with the OS .25 VRDF that Komet will see top speeds of about 165 mph applying the Graupner speed prop 6.5x6.5, shortened to 5.5“ diameter. If you find a well designed speed prop sized 5.5x7.5" the top speed will even reach about 175 mph! [sm=tongue_smile.gif]
Use the MACS tuned pipe #1120 set at a pipe length of ca. 23.5 cm between glow plug and middle of the pipe belly. The pipe will be completely hidden within the fuselage of the Me-163 if you mount the engine upright.
Generally all of the well known countermeasures to gain more speed (increasing compression ratio, smaller prop dia, more prop pitch, shorter pipe length etc) will be much much more effective if you combine them with an aerodynamically refined speed airframe.
Other well suited speed planes (low drag) for a .20 to .35 sized high-timed rear exhaust engine are the:
[ul][*] Beretta .21 by RC-Technik[*] Stinger .21 by RC-Technik[*] Stiletto .21 by RC-Technik[*] AJ-2 QM15 by Matney[*] Avia B-35 by Horrido[*] Spitfire MK 6-7 by Dieter Brandau
and numerous others...
[/ul]
So there are enough options to apply the OS .25 VR-DF effectively. Just check out this thread for more info:
Or alternatively design and build your own (or teamwork) super low drag speed airfame featuring fully cowled engine/pipe; fillets; well suited airfoils for wing, stab and vertical fin; internally hidden linkages; no hinge gaps etc. If your design turns out to be very successful (e.g. true 180 mph top speed with only 2.5 cc of engine capacity), you will most probably find someone making molds of it...
08-28-2009, 04:03 PM
#50
Senior Member
My Feedback: (44)
Join Date: Feb 2008
Location: kuna,
ID
Posts: 896
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrike .10-OS .25 vrdf project
something has been bothering me about your engine performance, i just went back and looked at earlier pics in this thread, and your coupler is hiding the end of the header and pipe, but i have the same setup here for that engine and the pipe slides over the end of the header until the o-rings are captured, and from the pics you posted you are at least a 3/4 inch long by not having the wizard pipe fully engaged, this is very critical to peak performance for this setup , i am positive you will see this engine really come on alot harder that you have experienced so far, hope this makes your day
, if you dont have the o-rings a trip to the hardware store will get you what you need.....
, if you dont have the o-rings a trip to the hardware store will get you what you need.....