Rocketry Warehouse Mouse 38

For those of you who picked up a Mouse 38 be advised this rocket will likely need nose weight.
I made a Rocksim file and even with one grain motors I had to add 4oz of nose weight to keep comfortably stable as barebones.
This is just a FYI...
here is my (updated)version of Rocksim file, I forgot this in 1st version
1. I added the mass of epoxy at the tip of the nosecone
2. semi span was a little shy, so made that a touch wider
all parts were weighed, and this is barebones, add your own accessories

View attachment mouse 38.rkt

Hey Jim,
Some of your part weights were a bit off. Played around with the rocksim file and the stability improved quite a bit.

View attachment mouse 38.rkt

Slickwilly said:

Hey Jim,
Some of your part weights were a bit off. Played around with the rocksim file and the stability improved quite a bit.

Click to expand...

That model seems to work better. Only needed 2.5 ounces in the nose to stabilize it for 1gn motors. I haven't received mine yet, but once I do I usually like to update with actual weights.

The RW description says "Weight Under 1 Lb" so I would expect it to be between 14 to 15.9 oz built weight. Banzai, your file still has it just over 11 oz. I suspect when it's built and weighed you will find you don't need any nose weight at all.

I'll wait until someone has built a kit and determined for sure if weight is needed rather then get excited over assumptions made about unconfirmed weights in an inaccurate sim.

After reading this thread, I got mine out, and weighed all the parts. It's not assembled yet. I came up with a weight of 8.35 oz., and my open rocket sim shows I need 5 oz. of nose weight. I has plans to put a Slimline retainer on the end, but the motor mount is a tad too short, and I don't want the extra weight back there. When it warms up enough I'll epoxy this thing together, and see just how much weight I really need to add. My sims show this to be a great performer on the "F" and small "G" motors. Phil L.

Just found this thread. I completed a Mouse 38 kit over the weekend. Cute little rocket. It is interesting to note the Rocksim file that was posted by Jimmy F. and modified by Slickwilly has component dimensions different to what I received. Specifically my nosecone measures 6 3/8" not 6" from tip to base (without coupler). My fins are 4 7/8" at the root not 4 1/2" and are positioned 3/4" from the rear not 1/2". I don't know if this reflects different production dimensions but this is what I received in my kit. A side note. I noticed that if you click on MORE in the posted Rocksim files it says the designer is Mike from Madcow?? There is also a fin flutter spec there. I wonder if these comments were carryovers from another Rocksim file that was modified to produce the Mouse 38 one?



My nosecone coupler needed much sanding just to get it into the nosecone and it goes into the cone 1/2" of its 3" length. My kit came without a nose cone bulk plate (an omission I believe). There was enough length in the 6" motor tube to allow for an Aeropack 29 mm motor retainer to fit perfectly. My kit is now fully assembled and with 10 Feet of Kevlar weighs 9.1 Oz. Add an 18" Perfectflite chute a Kevlar chute protector and two 1/8" quick links and it comes in at 11 Oz even. Measured C/G w/o motor is 11 7/8" from the nose which gives a static margin of 1.77. Adding a motor like an AT F20-7W gives a measured C/G of 13 7/8" which will produce unstable flight (0.01 Neutral) so it needs some nose weight. Adding 2.5 Oz. centered at 2 1/2" from the nose (remember the nose has a solid point extending 2" AFT) gives a margin of 1.04 with said motor. I will not actually add the nose weight yet until I sim the design with longer motors in case I need more than 2.5 Oz.

The only issue I had with the kit is that the fin slots were not cut equidistant, two being spaced 35mm apart and the 3rd being 32mm. I discovered this only after glueing the fins in place and trying to set the fins perpendicular to the body while maintaining equal tip spacing before the RocketPoxy set. I opted for equal tip spacing which I hope will make the rocket fly truer than had I set the fins perpendicular to the body.

After playing with the posted Rocksim file to make it match my measurements and actual measured C/G I have attached the corrected version here.

Davie, where did you find those rail buttons?

bill2654 said:

Davie, where did you find those rail buttons?

Click to expand...

I got a sample pair at LDRS last summer from Andrew of Additive Aerospace, the same fellow who makes the 3D printed avbay sleds and camera housings. Wildman now offers them here: https://www.wildmanrocketry.com/ProductDetail.aspx?product=7100. I glued them on with AeroPoxy and put a button head 4-40 x 1/4" machine screw in as well, more for a finished look than anything else.

DavieRockets said:

Just found this thread. I completed a Mouse 38 kit over the weekend. Cute little rocket. It is interesting to note the Rocksim file that was posted by Jimmy F. and modified by Slickwilly has component dimensions different to what I received. Specifically my nosecone measures 6 3/8" not 6" from tip to base (without coupler). My fins are 4 7/8" at the root not 4 1/2" and are positioned 3/4" from the rear not 1/2". I don't know if this reflects different production dimensions but this is what I received in my kit. A side note. I noticed that if you click on MORE in the posted Rocksim files it says the designer is Mike from Madcow?? There is also a fin flutter spec there. I wonder if these comments were carryovers from another Rocksim file that was modified to produce the Mouse 38 one?



My nosecone coupler needed much sanding just to get it into the nosecone and it goes into the cone 1/2" of its 3" length. My kit came without a nose cone bulk plate (an omission I believe). There was enough length in the 6" motor tube to allow for an Aeropack 29 mm motor retainer to fit perfectly. My kit is now fully assembled and with 10 Feet of Kevlar weighs 9.1 Oz. Add an 18" Perfectflite chute a Kevlar chute protector and two 1/8" quick links and it comes in at 11 Oz even. Measured C/G w/o motor is 11 7/8" from the nose which gives a static margin of 1.77. Adding a motor like an AT F20-7W gives a measured C/G of 13 7/8" which will produce unstable flight (0.01 Neutral) so it needs some nose weight. Adding 2.5 Oz. centered at 2 1/2" from the nose (remember the nose has a solid point extending 2" AFT) gives a margin of 1.04 with said motor. I will not actually add the nose weight yet until I sim the design with longer motors in case I need more than 2.5 Oz.

The only issue I had with the kit is that the fin slots were not cut equidistant, two being spaced 35mm apart and the 3rd being 32mm. I discovered this only after glueing the fins in place and trying to set the fins perpendicular to the body while maintaining equal tip spacing before the RocketPoxy set. I opted for equal tip spacing which I hope will make the rocket fly truer than had I set the fins perpendicular to the body.

After playing with the posted Rocksim file to make it match my measurements and actual measured C/G I have attached the corrected version here.

View attachment 279732 View attachment 279733

Click to expand...

Ha!
Yes, started with a Madcow 1.6 Screech file to 'make' the Mouse 38 file. That is why the Mike Stoop stuff is in there.
My apologies for that confusion. If you check my sim file you will find it is more acurate to the actual kit parts, just like yours DavieRockets. Not too sure where Slickwilly got his data. I just posted that file as a PSA, hoping to help those less experienced builders/flyers avoid any potential mishaps.

Anyone actually flown their Mouse yet? What did you all decide on for nose weight? I keep coming up with needing 5.9 ounces!! :jaw:

Banzai88 said:

Anyone actually flown their Mouse yet? What did you all decide on for nose weight? I keep coming up with needing 5.9 ounces!! :jaw:

Click to expand...

I flew mine on a G80 a few months ago. IIRC I added 3oz of nose weight, flew great.

Hmmmm, I've double checked my OR file several times, just can't seem to get it to sim right.

EDIT: OK, figured it out. 3.8grams of lead shot and rocketpoxy seems to have done the trick! Makes it .6-.7 cal stable for any CTI 1g motor with plenty of speed off of the rail. Should be good for just under 1K up to about 1700 ft. I'll have to fly it with an Alt 2 and see what it tells me.

Here is the OR Mouse file I made back in December, as I said it flew great on the AT G80T

View attachment Mouse.ork

Banzai88 said:

Anyone actually flown their Mouse yet? What did you all decide on for nose weight? I keep coming up with needing 5.9 ounces!! :jaw:

Click to expand...

Apologies for not following up on my original post. I finally added 3 Oz of lead shot mixed with Gorilla Glue inside the tip of the nosecone. I flew it on an Aerotech F20-7 Fast Jack in March and it flew beautifully to about 1200 feet.



Too fast for my Camera: