HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 15, 2012, 02:09 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,308 Posts
Question about the O-rings...Are they really necessary? Do they simply help stabilize the thrust tubes under high vibration?
Aros is offline Find More Posts by Aros
RCG Plus Member
Sign up now
to remove ads between posts
Old Mar 15, 2012, 05:30 PM
Registered User
Joe 1320's Avatar
United States, FL, Sebring
Joined Feb 2006
7,403 Posts
Quote:
Originally Posted by Aros View Post
Question about the O-rings...Are they really necessary? Do they simply help stabilize the thrust tubes under high vibration?
Actually, the afterburnerz with their raised LEDs offer support to the thrust tubes. One customer decided not to use the centering rings, he just installed the afterburners and the thrust tubes slipped right in and were held in place perfectly. With the support of the afterburnerz, I would say that the centering ring is necessary.
Joe 1320 is offline Find More Posts by Joe 1320
Reply With Quote
Old Mar 15, 2012, 05:45 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,308 Posts
Interesting...I don't see how the raised LEDs are supporting the thrust tubes? Am I missing something? On a good note, even with the tear in one of my tubes, I tried a WOT test today and they held great! The LED kit needs to be lightly CA'd in spots to keep from moving around though...I just don't want to glue them too much in the event I need to take them out like last time where the wiring ripped out...
Aros is offline Find More Posts by Aros
RCG Plus Member
Old Mar 15, 2012, 06:28 PM
Registered User
Joe 1320's Avatar
United States, FL, Sebring
Joined Feb 2006
7,403 Posts
Quote:
Originally Posted by Aros View Post
Interesting...I don't see how the raised LEDs are supporting the thrust tubes? Am I missing something? On a good note, even with the tear in one of my tubes, I tried a WOT test today and they held great! The LED kit needs to be lightly CA'd in spots to keep from moving around though...I just don't want to glue them too much in the event I need to take them out like last time where the wiring ripped out...
Don't use CA. Use a silicone type foam safe glue. You could use some clear gorilla glue (polyurethane), GWS glue,, I've seen good results with a glue found at Michael's that is a white, foam safe glue. I'll dig up the name of it when I get back in the states.
Joe 1320 is offline Find More Posts by Joe 1320
Reply With Quote
Old Mar 15, 2012, 06:31 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,308 Posts
Oh good idea...I have a glue gun too...
Aros is offline Find More Posts by Aros
RCG Plus Member
Old Mar 15, 2012, 06:32 PM
Registered User
Joe 1320's Avatar
United States, FL, Sebring
Joined Feb 2006
7,403 Posts
Quote:
Originally Posted by Aros View Post
Oh good idea...I have a glue gun too...
There ya go...... a few drops of hot glue will work great.
Joe 1320 is offline Find More Posts by Joe 1320
Reply With Quote
Old Mar 15, 2012, 06:33 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,308 Posts
I rely on CA and epoxy waaaay waaaay too much.
Aros is offline Find More Posts by Aros
RCG Plus Member
Old Mar 15, 2012, 06:36 PM
Registered User
Joe 1320's Avatar
United States, FL, Sebring
Joined Feb 2006
7,403 Posts
Quote:
Originally Posted by Aros View Post
I rely on CA and epoxy waaaay waaaay too much.
I must have 12 different types of glue in my adhesive box. Different types of CA, different types of Epoxy, foam safe glue, polyurethane, hot glue, you name it......
Joe 1320 is offline Find More Posts by Joe 1320
Reply With Quote
Old Mar 15, 2012, 10:51 PM
Shameful Warbirdaholic.
Aros's Avatar
Maple Valley, WA
Joined Apr 2006
8,308 Posts
My high start arrived tonight. I realized the tubing was the smaller diameter but I think it should be okay still. It's pretty resilient and strong rubber tubing. Besides AUW on the Blackbird isn't much if any heavier than a lot of the 2M-3M sailplanes these high starts are meant for.

One thing that I have been thinking about lately is the location of the tow hook. I'll have to do my research but I'm fairly certain the sweet spot is somewhere just in front of the CG. The problem is, on this plane, just in front of the CG is the receiver compartment. There's nowhere to mount a tow hook there. I may have to mount some thin wood like a bracket that spans perpendicular to the length of the compartment with epoxy, strong enough to support a tow hook and its use.

Well, I'm still a good two months out before official flying season hits here in the Pacific Northwest so that should give me ample time to find the right solution and setup. I can't botch this. A bad hand toss and you're gluing the front end back together. A bad high start launch and your picking out the electronics and throwing the rest of the plane into a plastic bag.
Aros is offline Find More Posts by Aros
RCG Plus Member
Old Mar 16, 2012, 10:41 PM
Wonderfully Wicked
The Don's Avatar
Willoughby, Ohio
Joined Jan 2002
12,962 Posts
Finished my SR-71. The maiden will be tomorrow. We are having unusually warm weather in Ohio this year for March, no snow and 65 degrees and 5 mph wind for the morning :-)

Is the recommended CG on the MaxJet correct or at least close? Ran it up on two 4S 2200 lipos and about 1:1 at just over half throttle :-)
The Don is offline Find More Posts by The Don
RCG Plus Member
Old Mar 17, 2012, 07:50 AM
Registered User
sanman55's Avatar
powder springs georgia
Joined Nov 2003
1,969 Posts
Wow...that baby is ready to go....what was your final weight???
Have a good maiden
sanman55 is offline Find More Posts by sanman55
Reply With Quote
Old Mar 17, 2012, 08:27 AM
Wonderfully Wicked
The Don's Avatar
Willoughby, Ohio
Joined Jan 2002
12,962 Posts
29.3 ounces with no lipo, 48.4 ounces with two 4S 2200 40C lipos.

Don
The Don is offline Find More Posts by The Don
RCG Plus Member
Old Mar 17, 2012, 10:38 AM
Build'm,Fly'm,Crash'm
redlite's Avatar
Sacramento CA
Joined Oct 2009
629 Posts
[QUOTE=

Is the recommended CG on the MaxJet correct or at least close? QUOTE]

Can't say, Don, I have both versions, but only built the LX...seeing how MJ copied everything else on the model, I would figure the CG is the same.

Good luck on the maiden...

Joe
redlite is offline Find More Posts by redlite
Reply With Quote
Old Mar 17, 2012, 02:32 PM
Wonderfully Wicked
The Don's Avatar
Willoughby, Ohio
Joined Jan 2002
12,962 Posts
Maiden was a success! CG was spot on. I forgot how cool a SR71 looks in the air. It really slows in turns if you get to tight so best to make larch flat turn with this one to keep it up on step. I was expecting more speed for the watts though, I wonder if all the surface texturing on this model is slowing it down. I don't recall the LX version having all the molded in detail.
The Don is offline Find More Posts by The Don
RCG Plus Member
Old Mar 17, 2012, 02:55 PM
Build'm,Fly'm,Crash'm
redlite's Avatar
Sacramento CA
Joined Oct 2009
629 Posts
Congrats, never doubted it...

The LX has more surface detail than the MJ, which makes it better for scale looks, if needed...MJ also has a smoother foam finish and shiny paint, better for speed models.

Most draggy model we have...shut the power off when it goes overhead so you can hear the air resistance and be prepared for a sound you're not expecting, being a SR-71 and all...

Joe
redlite is offline Find More Posts by redlite
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
SR-71 for EDF 50 (Closer than we might think) Thomas B Electric Ducted Fan Jet Talk 187 Feb 22, 2011 10:56 PM
SR-71 anyone? steve neill Electric Ducted Fan Jet Talk 71 Oct 08, 2007 07:34 AM
hobbylab sr 71 bushpilotx1 Sport Planes 7 Mar 06, 2002 12:53 AM
Electrics that can outperform the SR-71? SchiessCo Electric Plane Talk 4 Jul 30, 2001 08:44 PM