SparoAir air launched sounding rocket

The Sparoair 2 (my model) was developed at a time when some aircraft safe Sparrow
Missile motors were made available to the program

This allowed the Sparoair 2 to be launched directly from the aircraft.

The aircraft safe motors allowed for the electronic timer to be replaced with a simple
Delay switch timer

The payload cylinder was lengthened to 2.79 meters to allow for more payload volume.

The interstage was redesigned, lightened and made from cast aluminum

The 2nd stage fin area was increased by 1/3 to increase stability
Modified sparrow 2 fins Were used on the 2nd stage of the Sparoair 2

The timer package for the 2nd stage and umbilical plug was moved to the payload cylinder. The telemetry antenna was moved to the nose cone allowing the 2 external tunnels to be removed on the Sparoair 2

Note

All of the above drawings are of the Sparrow 1 air to air missile
The booster of the Sparrow air to air missile was also used on the
Sparoair 1, 2 and 3 sounding rockets

The quickest way to tell the difference between the Sparrow 1 air to air missile
and the Sparoair 1 Sounding Rocket is ....

Sparrow 1 air to air missile had a conical nosecone

Sparoair 1 Sounding Rocket had a ogive nosecone

This is the resulting measurements of the Sparrow 1 air to air missile booster

that was also used on the Sparoair 1, 2 and 3 sounding rockets

Hope this does not confuse anyone

Test to calculate my error by using a 9" diameter instead of a 7.9921" diameter


NACA test model

Outside diameter = 9.00”

BT-60 Outside diameter = 1.64”


1.64 / 9.00 = 0.182”


Test measurement is for actual vehicle Booster Fin Span

Actual vehicle Booster Fin Span = 31.506”


To get Booster Fin Span for a BT-60 airframe

Multiply 31.506” by 0.182” which = 5.7340”


Booster Fin Span for a BT-60 airframe = 5.7340”

part 2 Test to calculate my error by using a 9" diameter instead of a 7.9921" diameter

Actual Vehicle


Diameter of Actual Vehicle is 7.9921”

BT-60 Outside diameter = 1.64”


1.64 / 7.9921” = 0.205”


Test measurement is for actual vehicle Booster Fin Span

Actual vehicle Booster Fin Span = 31.506”


To get Booster Fin Span for a BT-60 airframe

Multiply 31.506” by 0.205” which = 6.4587”


Booster Fin Span for a BT-60 airframe = 6.4587”

Results Test to calculate my error by using a 9" diameter instead of a 7.9921" diameter

6.4587” - 5.7340” = .7247”


So by using a diameter of 9” instead of the actual

Diameter of 7.9921 my measurement for the Scale BT-60

Model would be off by .7247” or almost a ¾ inch


So it pays to review ALL of your scale data to check for variations.

Read it on one day take notes and come back several days later and

read again taking notes and then compare your notes for and variations

bobby_hamill said:

Dave
I already have those photos ( thanks for posting ) The drawings above show the measurements for the booster. Note those external channels / tunnels on the outside of the 2nd stage ? They were removed on the Sparoair 2 Sounding Rocket

BUT the external channels / tunnels on the outside of the 2nd stage were present on the Sparoair 1 Sounding Rocket

Click to expand...

Bobby,

I thought you might already have them, but it never hurts to get data twice, rather than not at all.

I also found a YouTube video, but it might not be useful for your project.



Dave F.

Dave
Nice video that I have not seen.
The Sparrow 1 and 2 Air to Air missiles were about 15 to 20 years earlier than the AIM 7

bobby_hamill said:

Dave
Nice video that I have not seen.
The Sparrow 1 and 2 Air to Air missiles were about 15 to 20 years earlier than the AIM 7

Click to expand...

Bobbi

I wasn't sure if any of the data "carried over" or not . . .

Dave F.

Dave

No problem I would rather see some new data that does not "carry over" than miss
some data that did have data that "carried over"

This is the measurements for the Sparrow 1 Air to Air Missile Booster that was used on
the Sparoair 1 and 2 Sounding Rocket

Now on to the nosecone and payload section for the Sparoair 2 Sounding Rocket

As per one of the reports that aerostadt downloaded for me the Sparoair 1 Sounding Rocket
Nosecone was .92 meter ( 36.220" ) ogive and a diameter of 7.9921 inches

The payload section was made up of a .140 meter ( 5.5118") cylinder .92 meter ( 36.220" ) ogive nosecone

The Sparoair 2 Sounding Rocket had the same nosecone as the Sparoair 1 .92 meter ( 36.220" ) ogive

But the Sparoair 2 Sounding Rocket payload section was increased from a .140 meter ( 5.5118") cylinder to a 0.279 meter ( 10.984" ) cylinder

-----------------------------------------------------------------------------------------


Therefore the Sparoair 2 Payload Section is listed below

0.92 meter ( 36.220" ) ogive nosecone with a diameter of 7.9921 inches
0.279 meter ( 10.984" ) cylinder with a diameter of 7.9921 inches

NOTE

in post # 31 I posted....

The payload cylinder was lengthened to 2.79 meters to allow for more payload volume.

Due to a typo I misplaced the decimal point correct length should read 0.279 meter ( 10.984" )

I could not edit the post

Ok now we need to determine the 2nd stage length.
Here is how I obtained the measurement
Please refer to the attachment below



The section labeled A is the payload cylinder section with a known length of .279 meters ( 10.98 Inches ).

So I will be using the 10.98" as a measurement to use in the comparison.

I can copy and paste 3 sections of the 10.98" side by side with no over hang Section labeled B

Then if I add one more section of 10.98" there will be a small overhang Section labeled C.

If I take the overhang in Section labeled C and divide a 10.98" section I can get 12 sections inside the 10.98"

This is my calculations

cylinder = 10.98 "
10.98 x 3 = 32.94"
10.98 / 12 = 0.915"
10.98 - 0.915 =10.065"
32.94 + 10.065 = 43.005"
Stage 2 Length = 43.005 inches

Later on I obtained some data that informed me the total Length of the Sparoair 2 is 151.968 inches
With the given known measurements here is what I calculated

Total length = 151.968"
Nose cone = 36.22"
cylinder for payload = 10.98"
Booster 1st stage = 55.695"

NC + Cylinder +1 st Stage = 102.895"

Total Length 151.968" - known 102.895" = 49.073
second stage = 49.073"

Therefore if i use the given stage 2 length of 49.073" and subtract the estimated stage 2 length of 43.005"
I get a result of 6.068" That is not bad of an error in second stage length of only 6.068" inches

Bobby,

Probably, the angle that the photo was taken at is largely responsible for the discrepancy.

Dave F.

Bobby,

When you have time, there is a "scale project" I would love to have you apply your "certain set of skills" to .

Please send me an email to let me know : [email protected]

Thanks,

Dave F.

here are the measurements I have thus far for the Sparoair 2

Nosecone 36.22"
payload cylinder 10.98"
1st stage 55.695"
2nd stage 49.073"

Total length 151.968"

Dave
You got mail LOL

Ez2cDave said:

Bobby,

When you have time, there is a "scale project" I would love to have you apply your "certain set of skills" to .

Please send me an email to let me know : [email protected]

Thanks,

Dave F.

Click to expand...

Bet I can guess what the special project is.....

rharshberger said:

Bet I can guess what the special project is.....

Click to expand...

I bet you can, too !

Dave F.

SparoAir build will continue soon when the BT-60 tubing and
plywood centering rings comes in as I was informed it was shipped out on 14 January

bobby_hamill said:

SparoAir build will continue soon when the BT-60 tubing and
plywood centering rings comes in as I was informed it was shipped out on 14 January

Click to expand...

Bobby,

Looking forward to it !

Dave F.

Me too...

Mw three . . .

Looking forward to the build

-Bob

I forgot to order some BT-50 to BT-55 Birch centering rings So I am posting photos of the Nosecone and 2 fin cans printed with PETG by cwbullet

The fin cans were printed before I realize my error in measuring so the fin cans and nosecone are off by 3/4 inch to big. later on after this build I may do a 2 inch fiberglass airframe version and will correct the mistake then

This is my first time working with PTEG fin cans so it will be a learning experience

Great work cwbullet !!

got a lot of test fitting done today

I saw the weather report for my neck of the woods of low 70s to high 60s for the 3rd and 4th of February,
So I have been using Elmer's Wood Filler and sanding the 2 fin cans and nose cone so I can apply a few coats of primer
on the 3rd and 4th (weather and humidity permitting).

Got a chance to glue on the 3D printed booster fin can and some centering rings
using J B Weld 1 minute epoxy