Dynasoar Pegasus RC B/G from Arkansas

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OK, here is the rocket motor mount with the reinforcing foam, glued w/ Titebond:

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One of the supports is a little back from the end of the motor mount. When it was in place, couldn't get it to move without disrupting the motor; so, I left the support there.
 
Here is an overview of my radio setup:

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I am using a Tactic brand radio from Tower Hobbies, along with Futaba 3114 servos. Power will come from Dromida 3.7 volt [1s], 350 mAh lipo battery. (There are two in the pic.) Got my soldering gear out; may a connector to go from the battery to the receiver.
 
I haven't used that brand of rx/tx or servo in this application, and I normally use a lipo that is a little bigger, you might want to test to be sure your battery doesn't droop under load with this rx/servo combination and brown out. Unless of course you have tried it.
 
I haven't used that brand of rx/tx or servo in this application, and I normally use a lipo that is a little bigger, you might want to test to be sure your battery doesn't droop under load with this rx/servo combination and brown out. Unless of course you have tried it.

So, I did a test. To begin, note that Dynasoar recommends a 3.7v, 1s 500 mAh battery to power your rocket glider.

Looking at the Horizon Hobbies website, I noted that they were using a 3.7v 150 mAh battery for a E-flite "Whipit" RC glider:
https://www.horizonhobby.com/produc.../sailplanes/umx-whipit-dlg-bnf-basic-eflu3150

Somehow in all this, I chose the 3.7v 350 mAh Lipo battery from Dromida (Hobbico/Tower Hobbies).

Let's test the power system! :wink:

Plugged battery into receiver, with my two 3114 servos.

The TEST: 3 minutes - let system sit, followed by 2 minutes of vigorous movement.

First test: Initial voltage - 3.98 ....... Final voltage - 3.93

Second test: Initial voltage - 3.94 ....... Final voltage - 3.91

The Second Test was conducted after a 5 minute break (unplugged).

Watching video on Pegasus in flight, seemed to take about 1-1/2 minutes to glide down after launch.
 
You are probably fine, a fresh charge should be closer to 4.2, but that's ok, I worry more about dips during loading than final voltage but if you aren't losing lock, should be fine. I'm doing up to 12 flights on a battery and only putting back 150mah.

Frank
 
Moving right along.....for the next steps, I decided to use "hot glue", which I got from Walmart (this has worked well on several RC jets):

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I will be using a launch rod, so I attached the Launch Lug (or Launch Tube). When you order from Dynasoar, you have an option of ordering a Lug or Rail Buttons:

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I chose this location so that the Lug can be hot glued to the Tube and the Wing. The servo was added after the Lug was attached.
 
A word on posting pics:

I have noted that, if I post pics late at night sometimes, the pics do not "process", and I get these 'attachment' messages. Not sure what I am doing wrong.

I am using a program called "PhotoRazor" to resize my pics to a smaller size for uploading.
 
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"Back in the USSR; you don't know how lucky you are, boys...."

Decided to go with a Russian look:

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This wasn't my original plan. These red stars were originally meant for my P-39 fighter (WW2), but I decided to go USA - North Africa. What to do with the red stars? Eureka!
 
I decided to put my receiver in the nose cone, along with the battery. Put velcro on the receiver & batteries:

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And, in the nosecone:

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Test the paint:

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Using the recommended Testors Model Masters paint. There is also a piece of scrap foam in the kit for testing paint.
 
If you weren't too heavy handed with glue and the extra thick pushrods it shouldn't take too much nose weight, let me know what your final flight weight winds up.

Weighed my Pegasus tonight with battery & motor. Came out to 362 grams (12.76 oz).

I added two 1/4 oz weights to the nose (came with kit). Note that I have my servos 3 inches forward of yours.

The Pegasus is listed as 12 oz (when built to instructions).
 
That weight is as shown, which is unpainted with the vinyl trim and using my components. Paint can add .25 to 1/2 ounce but your servos are lighter than mine and further forward...and your rx is heavier which would be a wash..I would have thought you might not need nose weight. did you need both weights to have the right cg?

Yes.
 
I double checked my prototype and it is at 358 grams rtf, so you are right on target, The kit card weight was incorrect, you are close to where mine is.

Interestingly the Estes nose cones have a variation in weight from 34 grams to 43 grams depending on how thick they were blow molded...My nose cone with nose weight is 57 grams but only needed 1/4 ounce of weight, if your cone was on the light end that would explain needing the full 1/2 ounce.

Now on to radio setup and flying!

Frank

BTW Since the servos are only about 6" from the CG, if you do a quick moments calculation, at your servo weight moving them forward 3" would save around 2 grams of nose weight but will require slightly longer/stiffer/heavier pushrods, since you moved the receiver to the nose, the servo extensions can't be shortened compared to what I used so in the end it was probably a net zero. Till I did the calculation I thought it would buy you more than it did just from gut feel. That's the advantage in a very long nose.

Servos are about 8 grams, initial moment to the cg was 16 grams x 6", new moment is 16 grams x 3", difference is 48 gram inches since the inside of the nose is about 23" from the CG to equal that 48 gram inch reduction, you would have to divide 48 gram-inches by 23" which yields 2 grams..Even if you make the servos 11 grams each and move the distance to 7" from cg it still is around 3 grams.


 
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Frank, any thoughts on a maximum wind speed for launch? How does the Pegasus tend to react to the wind?
 
Hi, that all depends on your trim and your piloting. I've flown them in over 10mph winds, once it is off the rail and into the wind they handle just fine. However if you don't have a good boost trim and have to react to gusts at the same time, it might be a challenge. You also have to watch changing gusts that are. I'd say a 5-7mph wind is no problem for a maiden flight. Since they are light they won't penetrate a high wind, so you don't want to get too far downwind on landing.

Frank


Frank, any thoughts on a maximum wind speed for launch? How does the Pegasus tend to react to the wind?
 
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