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Is anyone out there using an altimeter to record altitude during test flights in their F/F models? I know there are some very light units available now, and figure some of the FAI guys must be using them to test climb performance. Anyone?
~JimI have just set up a RAM2. Randall Brust built a few from leftover parts while waiting for the improved, smaller and lighter RAM3 stuff to arrive.
No results as yet.
Ken Bauer also has a fine unit from what I hear.
Ken Bauer’s name keeps popping up…
I have some question I would like to ask him, does anyone have an E-mail address fpr Ken they could share?
~JimThe is a review in the UK ‘Free Flight Forum’ 2006 of all the atimeters available at that time. This includes the Alti2, Ram2 and Bauer items. There is also sets of results from F1As with the first two units on board.
I’ve been using this altimeter in RC rocket-boosted gliders for about 2 years now. it is much smaller and lighter than the RAM2 unit (and probably most others). Also, the basic unit is inexpensive ($35) and reads out via an on-board LED (no computer needed).
I haven’t adapted one to a dedicated battery for FF, but it would do so easily… minimum input voltage is 3.2v, so a single LiPo would work.
Limitation is that in this configuration, it’ll only ready peak altitude… so use it for climb testing with a fast DT.
Greg in Mississippi
P.S. There is a discussion going over in the model rocketry world about allowing the use of altimeters for altitude events. After reading about how easy it is to alter the altitude read by pressure-sensor altimeters based on where on the model they are mounted (which varies the ambient airflow), I am convinced this is a BAD IDEA! See the article referenced above for info on this.
This means that picking where to mount your altimeter is important for accurate readings. On top of the wing where air pressure will vary a lot based on speed is a poor location. Middle-top of the fuselage with protection from the oncoming airstream is probably a safe location.
I built a streamlined pod which contains the RAM2 and can be rubber-banded wherever space can be found. On my Gas models, this will be on the side of the pylon.
Still working on a plan to use my small PDA to read the output (thanks, George) so that I can read it in the field. Those of you with laptops will have no trouble.
If there is interest, I can post a photo of the pod.
Randall Brust built a few from leftover parts while waiting for the improved, smaller and lighter RAM3 stuff to arrive.
The RAM3’s have arrived.
Thanks,
RandyFirstly Ken is at airtek@verizon.net
There is a Palm program from Tapio Linkosalo that will read Ken’s, the RAM2 [and I assume the RAM3],and the LoLo altimters.
The big advantage of these 3 is that they show the whole flight not just the max altitude. It turns out in practice with a F1B it is very useful to see the different parts of the climb as well as measure the rate of desent for different parts of the glide. This is of much more use than the max altitude attained.
Roger Morrell
I finally got a few flights recorded on my RAM2. Unfortunately, I managed to fold the wing on my T-Bird 525 before getting down to some serious testing.
However, it has become clear to me that this tool is invaluable. I recorded the data on an old anvil of a laptop I bought at a flea market. Already I have more insight as to how the model is behaving in the climb and transition. My transition looked “perfect” from the ground. Many other fliers complemented me on its’ excellence. Actually, the RAM2 showed that it was losing about 20 feet off the top before actually gliding!!
I nearly have it fixed and now waiting for the March weather to subside and back to the test field.
Again, this is an excellent tool, and the RAM3 promises to be even better. 🙂 😀
Flydean,
“Many other fliers complemented me on its’ excellence. Actually, the RAM2 showed that it was losing about 20 feet off the top before actually gliding!! “
This is not a true model effect, it is an effect of the speed change of the model during transition giving false altitude reading. Get a copy of the forum report I noted and see the experiments there with F1A’s and F1C’s in the UK. You will find that whatever you did with the transition you would still see an apparent stall but it doesn’t happen.
I bought a Bauer Altimax this year and now prefer it over the Alti2 I had for most cases. I say most as you can’t (yet) download the Altimax numbers to a PC (only a Palm) and then compare different flights using sofwtare (ie overlaying two flights). This you can do with the Alti2 which is extremely useful. However, for F1A which I fly the Altimax is easier to set up, smaller and lighter. The Ram3 is good but starts recording as soon as you switch it one, the Bauer system works on a trigger altiture which means it doesn’t fill up the memory while waiting on the ground.
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