modifyed tethys

Hey everybody

for xmas my parents are getting me a tethys kit (sweet) and I wanna launch it on a I284W but wanna modify it to house the RRC2 altimeter

the problem is with all the weight at the top it is over stable and I have a add a 250g weight to the bottom

even though it has became more towards its optimum weight I still loose about 800ft of altitude and I like altitude

do ya think i should do the modifications


P.S thanks sandman for telling me how to post.

I wouldn't worry about over stability. The only weight I recommend adding at the bottom is a bigger motor.

I agree. I can't imagine having to add 250g to the bottom.

What makes you think it is too (much) overstable, because there is such a thing?

- Nick

first off, let me say that i'm not into HPR and have little experience. Also, I am not familiar with this kit.

That said, seems to me that if *over* stability is a real concern, I would consider reducing the fin area rather than adding weight to the tail. Same effect but doesn't impact altitude .

Interestingly, Jim, your comments reminded me of a Modification Article on my site.

He shortened the Span on his PML Phobos....

CLICK HERE

Enjoy,
Nick

Matt,

Curiosity got me and I grabbed the 38mm Tethys Rsim from PML. With an I284 it had around 1.2 calibers of stability (approx, I already cleared the sim). Also the optimal mass was well below the stock weight, so all added mass will reduce the max altitude.

???

thanx guys i didn't take reducing the area of the wing span but i have worked out that it's possible to take off the mods and fly it normally so i think i will only use the mods when i use a large motor (eg J800) when i get some money

Matt,

Here's a link to a page about my TRA L2 Cert flight on a Tethys. Mine also had RRC2 and 18" payload for the main chute.

This exact configuraction had flown 3 hours earlier on an I284.

Enjoy your Tethys, --Lance.