Lifting Bodies at MDRA

[MondoRoc]

Wow! WELCOME to the forum! I'm flattered that you are reading this thread.

Thanks. I'm looking forward to building one of your lifting body kits when it comes out!

 

[Dr.Zooch]

RBFED passes its static tests... if it wasn't rainin' like crazy I'd go flight test it.

Looks like a series of powered flight tests will take place at MDRA's ESL 125 too.

 

[luke strawalker]

Installation of the RBFED does add an issue to the lifting body in the area of the boost phase. Although it is seemingly small, the RBFED gives the lifting body a slight angle of attack when mounted on the booster. (see illustration) Depending on how you wiggle it on the mount, the AOA is between 4 and 9 degrees and is divergent from the intended flight path. What this equates to during actual boosted flight- could be nothing, could be really bad. Flight test will tell the story. My best thought is that it will mean nothing. I say this for two reasons. First, the onboard video of the Dr. Zooch Shuttle orbiter that was intentionally shot into heavy winds and sheer using an 18 mm D engine, clearly shows the nose of the orbiter moving up and down toward a similar divergent AOA of about 4 degrees with no real stability problems to the boost…

Does this also take into account the same factors that caused the AOA changes observed on the shuttle flights?? If it is 'slack' in the pin/lug mounting being taken out, it could compound the AOA to between 8-13 degrees, which might have an effect. OTOH it might not... or the lift induced might be negligible and easily overcome by the stabilizers of the main stack.

Interesting to find out... OL JR

 

[Dr.Zooch]

Yes- I considered that and moved the LB so as to give it the max divergence while on the mount.

Good thinking Luke, you've taken your first step into a larger universe. Use the force.

 

[luke strawalker]

Yes- I considered that and moved the LB so as to give it the max divergence while on the mount.

Good thinking Luke, you've taken your first step into a larger universe. Use the force.

Even a blind dog finds a bone once in awhile... LOL

Thanks and have a good one, and keep us apprised... I WANT ONE OF THESE!!!! OL JR

 

[MondoRoc]

I ordered one of your RTF Shuttle kits from Uncle Mike's today. Time to actually earn the title of "BAR".

Will the glider be available as a separate kit, do you think? It'd be neat to swap out the Shuttle orbiter for "something completely different" on launch days.

 

[Dr.Zooch]

Cool- Read the shuttle build thread on this forum and you'll find some great tips.

The idea of orbiter only kits is being given thought.

 

[luke strawalker]

Cool- Read the shuttle build thread on this forum and you'll find some great tips.

The idea of orbiter only kits is being given thought.

Hey this is a great idea... I'd buy some extra gliders so I could have all the different orbiters... Maybe even paint one like Drax's Moonraker 5 in the Bond film Moonraker... that'd be cool

Will the mounts be close enough to swap the LB and the shuttle on the stack?? Inquiring minds want to know! OL JR

 

[Dr.Zooch]

Will the mounts be close enough to swap the LB and the shuttle on the stack?? Inquiring minds want to know! OL JR

Not at this time- however, see the shuttle build thread for details

 

[lmerdan]

I've got another idea for the lug/testing hooks.

attach the lug to the bottom of the glider, then sandwich (mmmmm ham) the lug between two pieces of balsa set back a bit protecting the lug so it is not subject to any RBFED force...

 

[Dr.Zooch]

Hey- now there's a second good idea. I'll be testing that one as well- just so happens I have a second lifting body ready to fly at MDRA this weekend.

 

[Dr.Zooch]

The kit-type stack flew! Launched it at MDRA today on perfect weather for flyin' rockets day. The boost showed an abnormal amount of roll (probably caused by an SRB mis-alignment) but the rocket's path remained straight and did not corkscrew at all. At ejection the lifting body seperated cleanly and went into a very nice glide. In fact the LCO even said over the PA that it looked to him as if was well trimmed. The booster's 12" chute deployed properly and, to give an example of the Lifting Body's glide, the booster beat it to the ground. The RBFED (first version) functioned just fine. On landing, the booster had a big swing going on the end of the chute and an SRB was snapped off when it hit the ground (an easy fix in the days ahead). I will look at a larger chute, however. Anyhow, I hope we'll be looking at this in kit form in the weeks ahead- stay tuned.

 

[Dr.Zooch]

This month's MDRA launch resulted in yet another test of the Lifting body kit (notice how I never seem to stop testing the thing? That's half the fun.) I decided to fly the kit shape with some slight modification. I launched this one in, what I'd call the "reentry airframe" configuration. That is- the kit shape with its leading edges and nose blunted as if it were expected to be able to do a reentry from orbit and form a detached shockwave. I wanted to see if the two shapes had any different flight characteristics… they did.

The reentry version has a far greater descent angle in order to maintain a speed where it can fly with stability. It appears as if this slight change in shape spikes the drag almost exponentially. It’s an interesting result that goes beyond what I’d expected. I had expected drag to increase, but not this much. Although this will not delay the kit’s release, it will cause me to play around with the shape additionally… sometimes I wish I had a little wind tunnel.

 

[Medaforce649]

That is some interesting stuff doc. Maybe try increasing the wingspan or raising the elevator.