RRC3 sport vs RRC Extreme ???

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

V2rocketeer

Well-Known Member
Joined
Jul 29, 2012
Messages
211
Reaction score
0
Hi all

Looking at both of these altimeters from Missle works. I am wondering what exactly are the differences? Like the Raven is there anything you lose when you go with the extreme version over the sport version? I'm looking for a main/backup altimeter for several MD 54mm birds and not seeing the exact differnces in these 2 altimeters besides a few dollars and the difference in altitude that they are rated for. Doing the sims I'm not seeing many of my upcoming flights being subsonic so I need a good reliable system.




Thank you

Chris
 
Hi all

Looking at both of these altimeters from Missle works. I am wondering what exactly are the differences? Like the Raven is there anything you lose when you go with the extreme version over the sport version? I'm looking for a main/backup altimeter for several MD 54mm birds and not seeing the exact differnces in these 2 altimeters besides a few dollars and the difference in altitude that they are rated for. Doing the sims I'm not seeing many of my upcoming flights being subsonic so I need a good reliable system.




Thank you

Chris

The only difference is the altitude rating for the barometer circuit.
 
The difference is two fold. The first is the altitude it can work at/measure. The second difference is the capacitor. The sport unit has and electrolytic cap and the extreme has a solid dielectric. The solid will not evaporate/boil off under vacuum. I not sure why Jim offered two versions to be honest...maybe just offer the extreme and make life easy by one design and stock item. Just a thought anyways.


Mark Koelsch
Sent from my iPhone using Rocketry Forum
 
I can see by the discussion in this thread that I've not done an adequate job in presenting enough data when it comes to the Sport vs. the Xtreme RRC3 models.

First off, the ONLY difference between the two models is the brown-out cap type/chemistry.
Both models can fly to the rated 10 mbar / 100K MSL rated ceiling of the sensing system.

So why have 2 models (as Mark asks):

"For high reliabilty purposes, the 'Xtreme" Altimeter replaces the standard RRC3 electrolytic brownout capacitor with a solid-dielectric type for operations in virtual vacuum and near space conditions. Electrolytic capacitors have (semi-)liquid dielectrics, which can boil off in vacuum."

The electrolytic cap manufacturers that do post altitude ratings concur that 30-40K MSL is the maximum recommended operational ceiling for these components.
This is where the Sport model derives its limit from.

- Can you fly a Sport Model to 100K MSL? ... Yes
- Will your Sport Model electrolytic cap rupture and/or boil off dielectrics if flown to 100K MSL? ... Maybe, but it will probably be OK.

You want an Xtreme model when maybe, but it will probably be OK is not an acceptable answer.
That's why there are 2 versions of the RRC3.
 
Thanks Jim

That is interesting. I ordered the Extreme from my local dealer and just waiting for it to arrive now.

Thank you everyone else for helping out as well

Chris
 
Last edited:
I can see by the discussion in this thread that I've not done an adequate job in presenting enough data when it comes to the Sport vs. the Xtreme RRC3 models.

First off, the ONLY difference between the two models is the brown-out cap type/chemistry.
Both models can fly to the rated 10 mbar / 100K MSL rated ceiling of the sensing system.

So why have 2 models (as Mark asks):

"For high reliabilty purposes, the 'Xtreme" Altimeter replaces the standard RRC3 electrolytic brownout capacitor with a solid-dielectric type for operations in virtual vacuum and near space conditions. Electrolytic capacitors have (semi-)liquid dielectrics, which can boil off in vacuum."

The electrolytic cap manufacturers that do post altitude ratings concur that 30-40K MSL is the maximum recommended operational ceiling for these components.
This is where the Sport model derives its limit from.

- Can you fly a Sport Model to 100K MSL? ... Yes
- Will your Sport Model electrolytic cap rupture and/or boil off dielectrics if flown to 100K MSL? ... Maybe, but it will probably be OK.

You want an Xtreme model when maybe, but it will probably be OK is not an acceptable answer.
That's why there are 2 versions of the RRC3.

Thanks Jim! My dual pairs of Sports and Extremes showed up yesterday!

Hypothetical question...say an Extreme version were flown to 150,000' or so, what would the apogee event look like? IE: would it deploy early (at some point when the pressure difference becomes less than the readability of the unit?), near apogee, or late (after apogee, when the unit drops to a low enough altitude where pressure differential is once again noticed by the unit)?

Just curious for one of those ambitious projects that has the theoretical potential to reach such heights. My mind continuously wonders what would be most appropriate for such deployments on such a flight: baro based, accelerometer based, gps based, primitive timer.

Thanks!

-Eric-
 
Thanks Jim! My dual pairs of Sports and Extremes showed up yesterday!

Hypothetical question...say an Extreme version were flown to 150,000' or so, what would the apogee event look like? IE: would it deploy early (at some point when the pressure difference becomes less than the readability of the unit?), near apogee, or late (after apogee, when the unit drops to a low enough altitude where pressure differential is once again noticed by the unit)?

Just curious for one of those ambitious projects that has the theoretical potential to reach such heights. My mind continuously wonders what would be most appropriate for such deployments on such a flight: baro based, accelerometer based, gps based, primitive timer.

Thanks!

-Eric-

Trained monkey???? :wink:

Adrian
 
I got mine today and there is one other benefit to using the extreme version even if you don't plan on going high enough to boil off the electrolytic cap oil.

The dielectric cap is smaller, lighter weight, and will be less likely to pull loose on extreme high g flights. Which is the main reason I got that version.
 
Have you high-altitude aspirations??? Personally, I've not flown much above 40K ('05 with the 'Wimpy-Q' project).

When one looks back to the "sounding rocket" hey-days, they weren't recovering rockets from altitude, however they were deploying payloads at altitude with nothing more than the equivalent of a mechanical timer. Flying the RRC3 Xtreme to 150K would be outside of its operational ranges, hence one would need to reconsider how it would be utilized. It's conceivable that a combination of altitude and timing controls thru the Aux Event would be most appropriate in this instance for an near-apogee/post-apogee event.

There are other systems that fuse GPS/Inertial data streams which could also be considered for such high altitude projects... and of course we will need build thread for this project. ;)

Thanks Jim! My dual pairs of Sports and Extremes showed up yesterday!

Hypothetical question...say an Extreme version were flown to 150,000' or so, what would the apogee event look like? IE: would it deploy early (at some point when the pressure difference becomes less than the readability of the unit?), near apogee, or late (after apogee, when the unit drops to a low enough altitude where pressure differential is once again noticed by the unit)?

Just curious for one of those ambitious projects that has the theoretical potential to reach such heights. My mind continuously wonders what would be most appropriate for such deployments on such a flight: baro based, accelerometer based, gps based, primitive timer.

Thanks!

-Eric-
 
Back
Top