Radical Rocketry X-15 Build with Fuel Tanks & Ablative Scheme

[burkefj]

Thanks Frank. I thought as much -- Ken got both the 2x24mm cluster as well as the 1x29mm engine options so will fly lots of experimental variants. The full ventral was used with both engines but the white ablative scheme had a pretty narrow operating window.

Now Ken has started talking about the Ramjet (which I think only flew as a dummy)...

I guess only option is to build 3 or 4 models with the correct options and paint schemes

Yes and officially the A-2 was 29" longer, or 1.38" at this scale which would help reduce nose weight but then you'd need to extend or add in side tunnel spacers/extensions, Could also add tip pods experiments for the -1 and -3 birds as well..

If you wanted to be nerdy you could use a fine line sharpie and drawn an outline of the left hand window shutters that were kept closed during the boost phase..

Yes the ramjet flew as a dummy only.

Here's a photo of a mach 6.33 flight configuration of A-2 without ablative that used the tanks and you can see the left hand round window doesn't have the shutter on it yet as it was only needed to prevent the ablative from clogging the window for landing.

 

[RokitFlyr]

Nice build info.! Where did you mount the launch lugs / rail buttons ?

 

[Grog6]

If there's not a pic there, it probably doesn't exist. Unfortunately, most are in Black and white format.

 

[KenECoyote]

Afaik the tall ventral was not used with the tanks and white scheme in particular. Most flights did not use it after a certain time as it wasn't needed. The oval windows were added in the a-2 version to prevent cracking at high temp/speed when it was re built. Tall ventral helps stability though and most people won't know better.

Great point to bring up! I've added a note to the first post that I had added to my FB and earlier posts that this is a "Sport Scale-ish" build.

This was a build that was pretty much evolving as I went along and was a very rushed (most work done in 3 evenings) vs. the usual modeler who plans out what they want first and then builds (and corrects if needed).

My main goal was to see if it would fly with the tanks and "10' looks" was second after that. I think I was pretty close given I had added parts without even knowing if they belonged (ex. the rear helium tank).

 

[burkefj]

Great point to bring up! I've added a note to the first post that I had added to my FB and earlier posts that this is a "Sport Scale-ish" build.

This was a build that was pretty much evolving as I went along and was a very rushed (most work done in 3 evenings) vs. the usual modeler who plans out what they want first and then builds (and corrects if needed).

My main goal was to see if it would fly with the tanks and "10' looks" was second after that. I think I was pretty close given I had added parts without even knowing if they belonged (ex. the rear helium tank).

It could be that it did use the extended ventral on the first ablative coated flight to mach 4.95 but I cant find any photos of that flight. There are several photos of black test flights with tanks with the long ventral and different color schemes on the ventral and on the tanks.

There's also some photos of plain silver tanks being test fit to the aircraft while mounted on the B-52 and it has a sort of rectangular wedge-shaped scramjet dummy mounted on the short ventral that sticks back past the aircraft, as well as a black test flight with the round scramjet ventral mount that was used on the ablative test and caused the shockwave impingement heating burn throughs.

 

[KenECoyote]

Nice build info.! Where did you mount the launch lugs / rail buttons ?

Great question!

3D printed 1/4" launch lugs and 1010 buttons are provided. I was going to use the lugs, but also wanted to use mini buttons since I would first fly off the LP/MP pads and there isn't any 1010 rail there for my club (would also be overkill on LP/MP pads imo).

So initially there were some concerns brought up as to whether there would be room for a rail with the tanks and wedge tail in the way, but I figured on this on the bottom...

It looked like it would be close, but I felt it would just fit a mini rail that was 20mm wide and I could add the lugs on the other side. Micro would've been easier, but I felt that may be a bit small for this heavy rocket on G flights. YMMV

However, I didn't have a mini rail at home, so I wasn't sure about clearance. I did measure the back and it looked maybe 2mm shy due to the bottom corner of the wedge fin, so I filed a bit off there.

My club apparently very rarely ever uses the mini rail (I may even have been the last years prior), so it was a bit of a challenge trying to verify it was still there and available, but luckily it was.

Here's a test fitting at the field the day of the launch:

Sweet!

 

[burkefj]

Great question!

3D printed 1/4" launch lugs and 1010 buttons are provided. I was going to use the lugs, but also wanted to use mini buttons since I would first fly off the LP/MP pads and there isn't any 1010 rail there for my club (would also be overkill on LP/MP pads imo).

So initially there were some concerns brought up as to whether there would be room for a rail with the tanks and wedge tail in the way, but I figured on this on the bottom...
View attachment 580000
It looked like it would be close, but I felt it would just fit a mini rail that was 20mm wide and I could add the lugs on the other side. Micro would've been easier, but I felt that may be a bit small for this heavy rocket on G flights. YMMV
View attachment 580002
However, I didn't have a mini rail at home, so I wasn't sure about clearance. I did measure the back and it looked maybe 2mm shy due to the bottom corner of the wedge fin, so I filed a bit off there.

My club apparently very rarely ever uses the mini rail (I may even have been the last years prior), so it was a bit of a challenge trying to verify it was still there and available, but luckily it was.

Here's a test fitting at the field the day of the launch:
View attachment 580005
Sweet!

I'm glad that worked and fit, another option for a full size rail is the top right to mount rail buttons it should clear the canopy just fine,

 

[KenECoyote]

I'm glad that worked and fit, another option for a full size rail is the top right to mount rail buttons it should clear the canopy just fine,

Yeah, with the tanks attached, that may actually be a cool view in this case.

 

[BigMacDaddy]

Here's a test fitting at the field the day of the launch:
View attachment 580005
Sweet!

My dad used to say "Like it was born there!"

 

[KenECoyote]

I'll add that

My dad used to say "Like it was born there!"

I was saying "like it was meant to be!"

 

[BigMacDaddy]

It could be that it did use the extended ventral on the first ablative coated flight to mach 4.95 but I cant find any photos of that flight. There are several photos of black test flights with tanks with the long ventral and different color schemes on the ventral and on the tanks.

There's also some photos of plain silver tanks being test fit to the aircraft while mounted on the B-52 and it has a sort of rectangular wedge-shaped scramjet dummy mounted on the short ventral that sticks back past the aircraft, as well as a black test flight with the round scramjet ventral mount that was used on the ablative test and caused the shockwave impingement heating burn throughs.

View attachment 580006View attachment 580007

For everyone's reference -- the difference between the short and tall ventral fins is basically a rudder portion that could be opened and closed and was ejected prior to landing (landing gear was not long enough to accommodate it). The challenge is that most pictures are of landings or with the plane on the ground. So even if the plane flew with the rudder attached there might not be a readily-available picture with it attached.

 

[techrat]

Were you joking that you shouldn't get the rocket weighed with an ignitor attached because it's heavier? Then I replied thasometimes the rocket takes the ignitor along and then later you said it just happened to you?

That was me! And yes, I still insist that the rocket should be weighed without the ignitor (and masking tape), as 99% it leaves that behind as it leaves the pad, and doesn't count as flying weight..... although then also technically, it could also be argued that the rocket is already lighter as it leaves the rail/rod as some propellent has already burned away. But man, that is really getting into details.

 

[burkefj]

For everyone's reference -- the difference between the short and tall ventral fins is basically a rudder portion that could be opened and closed and was ejected prior to landing (landing gear was not long enough to accommodate it). The challenge is that most pictures are of landings or with the plane on the ground. So even if the plane flew with the rudder attached there might not be a readily-available picture with it attached.

You are close, the inboard dorsal fin and ventral fin meaning the portions that are closest to the body had split sections which could be opened to act as drag breaks but they used air resistance to push them back so you couldn't use them at low speed, the upper dorsal and the lower ventral that was jettisoned were fully pivoting and acted as rudders only. One of my books that lists every flight that was flown, many of the flights are documented to say that they did or did not have the ventral I just need to go look it up.

 

[Ez2cDave]

 

[KenECoyote]

Flight day!

So initially I was planning on first launching this without the tanks to see how it flies not only since it's a new build, but also for a baseline comparison.

However, when the time came, I made the call to just go for the first flight with the tanks because I felt confident enough based on my swing tests. YMMV

I loaded an F52-5C motor, set a JL Chute Release for 400', put it on the mini rail and asked for a heads up launch (I may have broken the club's "Heads Up" stamp that day lol).

The rocket on the rail looked very cool to me!


There was a light wind coming from behind us and as the rocket boosted, it weathercocked into the wind, meaning it arced overhead (making video tracking a hit or miss). I then said "UH-OH" because it was over the river and trees behind us; however the wind brought it back and the Chute Release deployed on queue, resulting in a nice landing just past the pad.
SUCCESS!!!


I hadn't fastened the tanks tightly since I originally planned on removing them, then I forgot that they were loose and one fell off on ejection and the other came off on landing (no damage and both recovered).

BMD said that the tanks are supposed to come off on flight!

 

[KenECoyote]

Here's the video (sorry I lost tracking as it flew overhead):

 

[KenECoyote]

Wait...there's more! This is a special "Two-fer" launch edition!

On sunday, the next day of our club launch, my friend Vic was there and we had talked about having an X-15 drag race between his Apogee version and my Radical Rocketry version!

He had flown his before and this time he wanted to try a bigger motor and brought along a G76. He said to me "I don't know if it's going to rip the wings off", which surprised me, but I had just taken a screenshot of the motor suggestions that morning for comparison and that motor was listed.

(The two different rocket kits side by side.)

For mine, I hadn't flown it without tanks yet, so I decided to go with an F44W (which is 24mm) using an adapter, remove the 2oz lead donut from the nose and (of course) no tanks.

The LCO said that the first one off the pads wins...

 

[KenECoyote]

Wait! There's still even more!

Since my friend's X-15 failed to launch, I asked him if he wanted a rematch.

He was kind enough to wait for me as I proceeded to make things a bit more interesting...


I wanted to try a cluster! I used two D16-4 Q-jets with 18mm to 24mm adapters. I had originally planned to try the cluster that day, so why not make it fun and a challenge?

This time both lifted off!



Edit Side Note: I found it very amusing that we somehow ended up with the black X-15 having white smoke while the white X-15 had black smoke.

 

[KenECoyote]

So I gotta say that I honestly love this kit and it's come through with flying colors. I couldn't have imagined having so much fun with it so far. The modular engine mount is tricky, but oh so cool when you get it right.

To me, it's a mini version of my beloved 4"D Hangar 11 X-15... another sturdy and cool rocket. This one's a winner... literally.

Thanks @BigMacDaddy !

 

[KenECoyote]

Now that things have slowed down a bit, I revisited finishing/refinishing this rocket.

I was considering painting it with an overall matte white to be closer to the ablative, but in the end decided that I liked the present finish since it was more dirt and stain resistant (our fields are in a "black dirt" area which has black soil that really stains).

The rear of the plane as well as the tops of the vertical stabilizers are black, silver or gray and I was planning on masking everything and spraying black first, but decided it would be too tricky and risky (black overspray on a white rocket is pretty noticeable!).

I ended up ordering a set of acrylic markers and painting the rear by hand. I like the end result!



Note: I had earlier spray painted the motor retaining ring. It was showing some exhaust stains, so this is overdue.

 

[David Schwantz]

I am looking for the FS color # for the X-15A. If anyone has it. Thanks.

 

[Ez2cDave]

I am looking for the FS color # for the X-15A. If anyone has it. Thanks.

Contact Michelle Evans, an expert on the X-15 !

[email protected]

 

[David Schwantz]

Thanks Dave, sent email.

 

[Ez2cDave]

Thanks Dave, sent email.

Good luck !

 

[David Schwantz]

Already got a response from Michelle, great info she had. Thanks again.

 

[Ez2cDave]

Already got a response from Michelle, great info she had. Thanks again.

I'll send you an "invoice" - LOL !

 

[David Schwantz]

 

[burkefj]

She's great, I'm trying to get the museum to invite her to come give her talk at the evergreen museum in McMinnville she's also put several of my RC X-15 rocket planes on her website as well as the documentation I provided on my 199 flights I did..down at the bottom page at this link http://www.mach25media.com/models.html. I also sent her some pictures of my version with the silver tanks