Jump to content


Photo

1/24 Scratchbuilt Grumman XP-50 Skyrocket


  • Please log in to reply
23 replies to this topic

#1 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 08 May 2018 - 12:38 AM

Just thought I'd start blogging this build because it's happening now even though the Bearcat is still #1 in production.  I sent the engines I designed in 3D to Shapeways today and figured that's the beginning kick off moment of commitment.  For those of you that know what the XP-50 was when you read the title, way to go, because I did not until a few weeks ago when I stumbled on it reading about Bob Hall, the Grumman designer and test pilot who almost died in it. I was intrigued. It's clearly the development of the somewhat better known  XF5F Skyrocket that the Navy rejected but with a new contract to build a better fighter prototype  for the Army Air Corps, Grumman took their lost baby to a new party. Unfortunately, as a prototype it always played second string to the XP-49, a better-engined P-38 more or less that was charming the Army until well it wasn't. Grumman was told to keep developing the Skyrocket because it had lots of promise, too. But while most testing went well, there was one day that did not go so well and that was the day a turbosupercharger detonated and wrecked the hydraulics. Unable to effectively land without hydraulics, Bob Hall  bailed and the Skyrocket crashed into a bay on Long Island. That was the end of that. 

 Grumman's Tigercat came along a few years later and actually learned many lessons from this plane, but it was another plane all together really. I felt really sorry for the little thing, something they estimated could go 427mph. 

 

ZIZVTE.png

 

2xIT7a.png

 

 

Here's the work on the engines I sent to print today. I'm experimenting with Black Acrylic as a material as I'm really pushing the detail here quite a bit and they say this is the ultimate for detail. Unlike the Bearcat's engine which has many cooling fins detailing the cylinders, this one has them all! I've learned lots of tricks in the year of 3D modelling now and can produce this in a few hours (instead of weeks). For the record it's a Wright R-1820 Cyclone. It's what powered the B-17 , the Dauntless, the DC-3, the Buffalo and the Duck (and others if you want to wikipedia it). Print cost is $23 each. I think it's just going to look boss with two radials ; something I just felt I had to do once I realized what 3D printing can do. 

 

 

mJ5d3X.png

 

Welp, that's it.  Stay tuned!  


Edited by Jim Barry, 08 May 2018 - 12:55 AM.

  • Starfighter, blackbetty, LSP_Kevin and 11 others like this

#2 NukerDan

NukerDan

    Member

  • LSP_Members
  • PipPip
  • 21 posts
  • Gender:Male
  • Location:Quartz Hill California

Posted 08 May 2018 - 01:24 AM

I'll be watching this! I love the obscure, lesser known aircraft of that era. Can't wait to see the result of the 3D printed engine!
  • harvey and Jim Barry like this

#3 Tnarg

Tnarg

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 1,918 posts
  • Gender:Male
  • Location:Santa Rosa, CA

Posted 08 May 2018 - 02:07 AM

What an amazing project. Love those big radials and the fine look of that aircraft.

 

Tnarg


  • harvey, Peterpools and Jim Barry like this

#4 Gazzas

Gazzas

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 2,951 posts
  • Gender:Male
  • Location:Queensland, Australia

Posted 08 May 2018 - 05:08 AM

This looks interesting!


  • harvey, Peterpools and Jim Barry like this

​We don't have social skills.  We build models.


#5 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 08 May 2018 - 12:03 PM

Thanks for the send off everyone .   For comparison you can see here how much higher fidelity this new engine is over the Bearcat's below.  

 

2bl7At.png


  • Starfighter, LSP_Kevin, harvey and 3 others like this

#6 Shawn M

Shawn M

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 6,277 posts
  • Gender:Male
  • Location:St. Louis

Posted 08 May 2018 - 12:48 PM

always loved this airplane!

Are you doing the trike or tail dragger?


  • harvey likes this

I dont suffer from AMS, I revell in it..get it...Revell


#7 Out2gtcha

Out2gtcha

    Senior Member

  • LSP Moderator
  • 23,020 posts
  • Gender:Male
  • Location:Omaha, NE US

Posted 08 May 2018 - 12:51 PM

Cooooooooooooooooooooooool! 


  • Jim Barry likes this

#8 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 10 May 2018 - 02:01 AM

Getting real tonight. 

 

Here's the spine . It's .08 sheet styrene but I only had 12 inches and will need to tack on a few more inches with some epoxy for the full length. Cut with a Dremel jigsaw but you have to be careful as the styrene will melt and reseal the cut if you cut too long and let the blade heat up. I learned that a while ago and it's nice to still remember the error. 

 

pcnrLb.jpg


  • Starfighter, LSP_Kevin, harvey and 4 others like this

#9 Dandiego

Dandiego

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 553 posts
  • Gender:Male
  • Location:San Diego

Posted 10 May 2018 - 03:36 AM

Jim,

I used 80 thou for the spine on the F-90. I just traced the shape, scored it with a knife and snapped it out. Worked for me, but then I don't own a jigsaw. Would have tried it your way if I did have a jigsaw.

I guess you make it work with whatever you have.

Dan
  • Jim Barry likes this

#10 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 13 May 2018 - 08:46 PM

Hi Dan, Common ground on our spine choice!  I've cut it with a knife with the Fury but when I thought about doing more scratch I decided a little jigsaw will pay off. Pretty happy with my purchase. I'll be using it a ton for the Skyrocket. 

 

So, in the news, the engines came back from Shapeways and I'm very happy. Turns out Black Acrylic was rejected by the engineers there so i just went back to good old Frosted Ultra Detail and it did just fine for half the cost. Just $24 for both engines. 

 

QvOzgj.png

 

 

asswi1.jpg


  • LSP_Kevin, Harold, harvey and 4 others like this

#11 Peterpools

Peterpools

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 25,202 posts
  • Gender:Male
  • Location:Ridge, New York

Posted 13 May 2018 - 11:06 PM

Will be following with great interest, as anything Grumman is near and dear, as I'm life long Long Islander and lived maybe 20 minutes from the Bethpage plant.

:popcorn: :popcorn: :popcorn:

Peter


XMoWX3.jpg

Fisher Sea Fury FB.II 


#12 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 14 May 2018 - 12:22 AM

Well then Peter you can certainly appreciate my weekend. Check out my visit  to the USS Yorktown and the haul of Grumman treasure there.  Have you ever made it there? 

 

Starting with the Wildcat: Fully resplendent and truly a lifetime favorite. Always good to see. 

 

GVV1QU.jpg

 

3AwVmQ.jpg

 

z3SLHq.jpg

 

Then the Hellcat. Such detail in real life. Staggering complexity to it all, really. I do not think I've ever seen one in real life (and have been to Duxford, Smithsonian Air and Space (both Dulles  and Downtown) , the  US Air Force Museum and years of airshows)

 

IEyoIN.jpg

 

The I was stunned by the size of an Avenger. A true brute. Not sure scale models ever do it justice. Great to see! That's a first too. 

 

QIwnoF.jpg

 

 

Then I got not only see an F9F Cougar,  but actually sit in it. I could not  believe it. I'm such a fan. I could work the buttons on the stick and move it around which was a nice treat in this day and age. This is a great museum! (and the Yorktown itself is mind blowing even without the aircraft)

 

Dmm9VZ.jpg

 

RlQsn8.jpg

 

Then up on the deck for a gorgeous Intruder

 

I5SXlI.jpg

 

and a beautiful Tracker complete with the same Wright R-1820s as the Skyrocket (though a little more modern version). There was also the rare EWACs Grumman Tracer but I did not get pictures (batts died!)

 

KHxtGg.jpg

 

 

And then the ultimate performance Grumman: 

 

The Tomcat:

 

9QW6h1.jpg

 

 

And for model enthusiast such as ourselves I was thrilled to see this (perhaps 1/9th scale??) Hellcat. Amazing attention to realism. 

 

zmgsNo.jpg

 

 

 

y2dEoN.jpg

 

 

pRv72v.jpg

 

 

Other cool things but outside my scope of Grumman pics for this thread  was a Skyraider, a Dauntless, a Corsair, a Corsair II, an F8 Crusader, an S3 Viking (thought of you Ben "Starfighter"), an F-18 Hornet,  a very nice F-4J , a Stearman PT-17 and a B-25. 


  • LSP_Kevin, harvey, HerculesPA_2 and 4 others like this

#13 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 16 May 2018 - 01:37 AM

Ok, Back to our previously scheduled programming...

 

Tonight was cowl night on the computer. The work doing this with the Bearcat was rather trying as I did not know how to do this in 3D. Much trial and error.  Now I do so, it's actually pretty easy. I like the photo I had to attach within Fusion for a test/validation of the cowling opening size against the real thing.

 

I ordered two tonight.  :)  :) 

 

Thwonv.png

 

5p5FEQ.png


  • harvey, sandokan, patricksparks and 1 other like this

#14 dodgem37

dodgem37

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 8,377 posts
  • Gender:Male
  • Location:Silver Spring, Maryland USA

Posted 16 May 2018 - 08:37 AM

Good show.

 

Sincerely,

Mark


  • Jim Barry likes this

#15 Jim Barry

Jim Barry

    Senior Member

  • LSP_Members
  • PipPipPipPipPipPip
  • 542 posts
  • Gender:Male
  • Location:Freeport, Maine USA

Posted 17 May 2018 - 04:07 AM

Thanks Mark, (and I get your forum name now. I was thinking Dodgem like Dodgem cars (bumper cars) but I get it. Dodge M37...your little treasure.  :)

 

 

 Tonight was a bit of toil throwing 3D work  into the trashcan kind of thing,  but in the end I think I got just what I wanted: Two counter rotating Curtiss Electric props. To feather the prop there's  an electric motor in the small hub at the tip  and large reduction gears in the large hub. Power is supplied by brushs that contact slip rings on other side of the blades. More here with a nice vintage guide   http://www.enginehistory.org/Propellers/Curtiss/curtissprop.shtml . If you are curious and want to know more, well the starboard side has the "handed" propeller. Handed means it turns clockwise (from the pilots perspective). The port side has a "counter-handed" propeller . 

 

t2YT5J.png


Edited by Jim Barry, 17 May 2018 - 04:09 AM.

  • Iain (32SIG), LSP_Kevin, harvey and 2 others like this




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users