SD's RamJet Build

[troj]

Looks good, Scrap.

-Kevin

 

[cjl]

the test flight should be on a 1/2 A6 so to minimize any potentual damage

How much does it weigh? A 1/2A6 won't get it very high...

 

[ScrapDaddy]

How much does it weigh? A 1/2A6 won't get it very high...

I am not quite sure, where can you get a little scale thingy? And if it is heavy, woops I didn't mean to say minimise I ment Maximise

 

[ScrapDaddy]

Looks good, Scrap.

-Kevin

Thanks, it's the first one I haven't totally messed up the paint Job on I hope I didn't jinx it if I find some decals I might be able to enter it in te spring contest (boy someone is being optimistic )

 

[cjl]

I am not quite sure, where can you get a little scale thingy? And if it is heavy, woops I didn't mean to say minimise I ment Maximise

Well, if you don't have any way of weighing it, I'd probably go with an A8-3 or B6-4 for the first flight, to ensure that it has adequate power to get off the launchpad safely, and adjust from there.

 

[troj]

I am not quite sure, where can you get a little scale thingy? And if it is heavy, woops I didn't mean to say minimise I ment Maximise

Do you have a postal scale available to you?

What you need is something like this. For LPR, I'd really suggest a scale that does 1/10 gram.

-Kevin

 

[ScrapDaddy]

Grr $20......Umm... I'll take a Crack at it with my A8's

 

[cjl]

I use these:
https://saveonscales.com/product_mw_mxt_series.html

 

[UPscaler]

I have one of these.
https://cgi.ebay.com/600-X-0-1-GRAM...emQQptZLH_DefaultDomain_0?hash=item3357605cde

It works great. It has been very useful. It has 4 different modes. It's pretty convenient. Nice to have around.

 

[ScrapDaddy]

$60 for a scale?!?!?!

 

[ScrapDaddy]

Well there are only 3 people unacounted for, MarkII, The EGE, and Ben

 

[The EGE]

Well there are only 3 people unacounted for, MarkII, The EGE, and Ben

Believe it or not, I don't own a scale. Well, except for the one that says I'm 138 lbs...

 

[ScrapDaddy]

Believe it or not, I don't own a scale. Well, except for the one that says I'm 138 lbs...

Well that leaveS MarkII and Ben


And The EGE, didn't you say you weighed all of your models after being built? And 138LB? That's light, I think

 

[Bone Daddy]

Very nice looking rocket. I've had a similarly built ramjet sitting on my workbench for a while now just waiting to be be used. This is just the encouragement I needed to get on with a design.

I'd look forward to a nice stable flight with chance of weather cocking. Have you thought about recovery? I find rockets with big fins like this are excellent candidates for streamer recovery.

If it were me, I'd light it up with an A8-3 followed by a B6-4.

 

[The EGE]

And The EGE, didn't you say you weighed all of your models after being built? And 138LB? That's light, I think

I guesstimate the weight. B6s are 20g (0.7oz), C6s are 25g (0.9 oz), D12s are 43g (1.5 oz), 29/40-120 hardware is 56g (2 oz), and 29/180 hardware is 84g (3 oz).

Yes, 138 lbs is rather light. I'm 6 foot even, so I'm right on the verge of being underweight.

I agree with Bone Daddy, big fins mean plenty of weather cocking, and a streamer should prolly be fine.

 

[ben_ullman]

front and center!

I own 2 rocket scales, a 5500gram .1g accurate scale for chems and other small weighing. Then a 300lb 1lb accurate scale for the larger stuff.

go with a B6-4. this looks pretty draggy.

Ben

 

[cjl]

front and center!

I own 2 rocket scales, a 5500gram .1g accurate scale for chems and other small weighing. Then a 300lb 1lb accurate scale for the larger stuff.

300lb?

Dang...

I have a 100g capacity scale accurate to 0.01g (epoxy, chemicals, small rockets), a 500g scale accurate to 0.1g (small rockets), and a 75lb postal scale accurate to half an ounce for >2lb, and 0.1oz for <2lb. I figure if it's over 75lb, I can just use the bathroom scale.

 

[ScrapDaddy]

Very nice looking rocket. I've had a similarly built ramjet sitting on my workbench for a while now just waiting to be be used. This is just the encouragement I needed to get on with a design.

I'd look forward to a nice stable flight with chance of weather cocking. Have you thought about recovery? I find rockets with big fins like this are excellent candidates for streamer recovery.

If it were me, I'd light it up with an A8-3 followed by a B6-4.

Well here's your motivation to get the ramjet finished, if you ever come by NY, let me know and we will have a drag race

I am worrried that the RamJet will move the CP to far forward.

 

[ScrapDaddy]

I guesstimate the weight. B6s are 20g (0.7oz), C6s are 25g (0.9 oz), D12s are 43g (1.5 oz), 29/40-120 hardware is 56g (2 oz), and 29/180 hardware is 84g (3 oz).

Yes, 138 lbs is rather light. I'm 6 foot even, so I'm right on the verge of being underweight.

I agree with Bone Daddy, big fins mean plenty of weather cocking, and a streamer should prolly be fine.

Oh, now I know why you stuck with 29mm machbusters, you have a bigger margin for "Guesstimation"

I am 93.4 LBs and 5' 3"

I am a firm believer in "Better safe than sorry"

 

[ScrapDaddy]

front and center!

I own 2 rocket scales, a 5500gram .1g accurate scale for chems and other small weighing. Then a 300lb 1lb accurate scale for the larger stuff.

go with a B6-4. this looks pretty draggy.

Ben

Hey Ben, it's nice to see you made it to this thread intact


Rocket scales are "privlages"


Ok I'll go with expertise on this one, first flight will now be on a B6-4 (I'll thank you later when I find out how low it flys )

 

[slogfilet]

Looking good!

As a side note, harbor Freight has some decent scales at times... $10-12 for a small digital one. Accurate enough fo my needs. =)

 

[cjl]

Well here's your motivation to get the ramjet finished, if you ever come by NY, let me know and we will have a drag race

I am worrried that the RamJet will move the CP to far forward.

Given your large fins, I'd say you're almost definitely going to have no problems with stability. You can always swing test to be sure though.

 

[ScrapDaddy]

Given your large fins, I'd say you're almost definitely going to have no problems with stability. You can always swing test to be sure though.

She is just begging for a 29mm upscale, speaking of which upscaler gave me a great idea for a paint job, a Metalic silver coat and then little pieces of oddly shaped tape followed by a coat with a metalic Blue coat, and voilà, a blue coat with silver shapes in it!

 

[dragon_rider10]

Whoah whoah whoah.... easy does it, remember. Fly what you have first, then you can talk about upscaling.

 

[troj]

Whoah whoah whoah.... easy does it, remember. Fly what you have first, then you can talk about upscaling.

Fly several more designs of your own creation, successfully, then consider upscaling one or two.

-Kevin

 

[dragon_rider10]

She is just begging for a 29mm upscale, speaking of which upscaler gave me a great idea for a paint job, a Metalic silver coat and then little pieces of oddly shaped tape followed by a coat with a metalic Blue coat, and voilà, a blue coat with silver shapes in it!

I saw a HPR rocket this weekend with a similar scheme, blue shapes on silver background:

https://www.nefar.net/gallery/2010-04/index.html

Last vid of on the page at the moment. A FANTASTIC flight. Highlight of the day.

 

[Micromeister]

If you watch the harbor frieight sales you can get a very nice pocket 500g .1g scale for under 10 bucks. I've been so happy with the first one I purchased I went back and got 3 more so I can have one handy at all times

Very nice to see a build thread from You SD...But that ain't no Ram-Jet...
these are Ram-Jets LOL!!!

Seriously tho... Good lookin build; for yours I'd go with a Bright Yellow or maybe orange with red & black strip details?

 

[ScrapDaddy]

Don't one up me I was hoping for more of a scifi theme. Your RamJet looks "modern" with swept-wings I used semi swept coward fins to make it look "futureistic".

FYI: I settled for a estes 18mm nose cone because I coulnt find a conical NC laying around.

 

[new2hpr]

If you're really tight on funds, or just don't want to buy a postal scale, use theirs! I took my L1 to the post office for an accurate weight for my sims. I did make sure to call ahead, as it was a 4" x 5'+ long rocket. Got some interesting looks, and surprisingly, no comments:eyepop:.

One quick question: With that fin shape, I can't tell which direction your grain is running, or if it's even possible to run it in the traditional "parallel to leading edge" direction. A paper skin would alleviate any strength issues there.

Looks different, refreshing change from 3FNC.
-Ken

 

[ScrapDaddy]

Ok, Micromeister will kill me here but....all the parts were from a Estes Richochet set ( that's right you can make one of these at home ) so I have to use what was avalible to me, unforunetly, this ment that the way I wanted the fins, the grain would be running perpentivular to the leading edge :jaw: I soaked these fins in MinWay wool hardener, which should really help.