Graupner's new HOTT 2.4GHz system. - Page 95 - RC Groups
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Feb 10, 2013, 08:51 AM
g0t rabb1t?
ABLomas's Avatar
Originally Posted by glmccready
One airframe, one Rx, SUM and PPM output from the same Rx? ie: SUM has to be from channel 8 (Mikrokopter) , can I also use channel 6 to control a device (Radian flight stabilizer) that needs PPM input.
I still do not get - why you need double PPM output?
You can use Y-cable and get PPM on two wires.
Or... Maybe you had in mind "PWM", not "PPM"?
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Feb 10, 2013, 10:24 AM
glmccready's Avatar
My channel 8 SUM goes to the Mikrokopter Flight control board. I also need one or two inputs to a Radian Flight stabilizer board. I know I can add another Rx (master/slave) but wondered if I can get output from one of the other plugs if plug 8 is using PPM SUM. The Mikrokopter can not use PWM (on channel 8, PPM/SUM) , the Radian can accept either S.Bus, PPM or PWM. I assume the 1-7 channels on the GR-24 are PWM and channel 8 is PPM?
So: Can I use PPM and PWM at the same time. I guess a "y" might work as well, but I don't want to interfere with signal to my flight controller. The Manual is semi worthless.
Feb 14, 2013, 03:02 PM
Registered User

CRASH: Graupner MC-20 and WKM with Cinestar 8

Lost radio contact at relatively short range. Graupner log files show Rx strength hitting 0-15% during time of contact loss.

The story:

250-300 yards out C8 started drifting away and not responding to control inputs.
I initiated a return-to-home. C8 responded and returned directly to takeoff position at altitude, but I was unable to cancel the failsafe or re-establish any radio control whatsoever.
C8 started counter-clockwise toilet bowl on descent and started drifting away from takeoff position. Just watched in horror as it kept coming down, toilet bowling, and eventually slammed into the side of a trailer with speed.
Three broken booms, 3 motors, 8 props. Coulda been worse. Luckily no damage to gimbal or camera.

I would deduce a combo of factors leading to this crash. Firstly, clearly a range issue with my Graupner system, and secondly a GPS issue with the WKM (attributed to the toilet-bowling as it seems GPS was seeking but not finding exact position). Then the failsafe lockout issue (WKM?) combined with pilot error - panic. There are some things I should have tried to reestablish radio control, like switching between flight modes, but I was expecting a nice autoland as I had experienced during tests, and when it started toilet-bowling there was not much time to react.

I have been flying this machine without issue for two months. On initial flights I tested the failsafe return-to-home and it worked perfectly all the way to landing.

What's new:
New location...kind of. I normally live and fly in North Carolina. This crash occurred in Utah. However I have had over 20 successful flights here in Utah prior to this crash. I did not recalibrate my compass/GPS upon arrival in Utah, so this could be a factor.

I checked internet for solar flares on that day and there was one - but not particularly significant.

The relatively short range that started the chain of events is most puzzling. It was about as far as I typically feel comfortable flying so I have not pushed beyond that, but obviously should be well below the range limits. I am pulling the Graupner data this morning to see what it shows.

I think the toilet bowling was my fault as I did not do the recalibration for magnetic deviations in Utah. This was a procedure I just honestly did not think about when I came out to Utah.

Question: What is the recommended failsafe setting within a Graupner MX (or MC) 20 in combo with the WKM failsafe?
Feb 14, 2013, 03:35 PM
g0t rabb1t?
ABLomas's Avatar
Originally Posted by mihlit
For those who would like to use FrSky together with MX-20/16/12, but don't know how to do it:
Great, thank you!
With some minor aditions, different components used, but ideas taken from this site... Result:

(a bit modified after i did photos, but... idea still the same)

Works OK so far. Gimbals sucks on MX-20 (yes, have ball bearings, but sooo soft plastic, cracked on bolt positions already), so probably more mods to add later ;-)
Feb 14, 2013, 04:06 PM
Registered User
HoTT prepare its backdoor... for the hard landing case.

Bookmark this site:
Everything there, and will come more, like 4 RC systems, is made by SJ, SJPropo
Google for their TS-4 car radio already reviewed.
Feb 14, 2013, 04:47 PM
Professional idiot
The naming is probably not the best: 'SJHIT'
Feb 14, 2013, 04:56 PM
Registered User
Originally Posted by ABLomas
Great, thank you!
With some minor aditions, different components used, but ideas taken from this site...
I'm glad it helped What changes did you make?

so probably more mods to add later ;-)
I made another mod - I moved those two pots from centre to sides, where most transmitters have them.

Btw, beware there is a bug in MX-20's firmware. If you switch models - one with RF module=EXT -> one with RF module=HoTT -> one with RF module=EXT then there will be no PPM signal present. The same happens if you turn on your radio with model that has RF module=HoTT and switch to some using EXT, again there will be no PPM signal present.
Feb 14, 2013, 09:05 PM
glmccready's Avatar
BryHarv: Sorry about your crash! I had a problem with my Graupner Mx-20. I was doing a range test, which had ended. When I started up my CS6 with MK FC it took off sideways and crashed as soon as I pushed the sticks to arm the motors. I only broke an arm, but it left me a bit gun shy. I think it went into failsafe because it lost the signal. Only thing i can think of, I was only 20ft away, and walking back after the range test. Must have still been in Range test mode. Have flown it flawlessly 30 times since with no problems. I no longer do the range test. I also use the "speaking" output telemetry to whisper the battery voltage and signal strength in my ear now.
Feb 20, 2013, 09:36 AM
Registered User
Das Ende:

Beschluss vom 13.02.2013

In dem Insolvenzeröffnungsverfahren über das Vermögen der

Graupner GmbH & Co. KG, Henriettenstr. 94-96, 73230 Kirchheim/Teck (AG Stuttgart, HRA 230523), vertr. d.: 1. Graupner Verwaltungs-GmbH, Henriettenstr. 94-96, 73230 Kirchheim/Teck, (persönlich haftende Gesellschafterin), vertr. d.: 1.1. Stefan Graupner, Henriettenstr. 94-96, 73230 Kirchheim/Teck, (Geschäftsführer)

ist heute, am 13.02.2013, um 16:20 Uhr, angeordnet worden (§§ 21, 22 InsO):

Zum vorläufigen Insolvenzverwalter wird Rechtsanwalt Dr. Wolfgang Bilgery, Reinsburgstraße 27, 70178 Stuttgart, Tel.: 0711/xxxxx-0, Fax: 0711/xxxxxx bestellt .

Verfügungen der Antragstellerin über Gegenstände ihres Vermögens sind nur noch mit Zustimmung des vorläufigen Insolvenzverwalters wirksam (§ 21 Abs. 2 Nr. 2 InsO).

Den Schuldnern der Antragstellerin (Drittschuldnern) wird verboten, an die Antragstellerin zu zahlen. Der vorläufige Insolvenzverwalter wird ermächtigt, Bankguthaben und sonstige Forderungen der Antragstellerin einzuziehen sowie eingehende Gelder entgegenzunehmen. Die Drittschuldner werden aufgefordert, nur noch unter Beachtung dieser Anordnung zu leisten (§ 23 Abs. 1 Satz 3 InsO).
Feb 20, 2013, 09:47 AM
Taranis Tyro...
MattyB's Avatar
Yep - I'm not a HoTT user, but this is very sad news. Graupner was a great name that goes back at least 3 generations (I believe a Graupner kit was the first plane my Dad and Grandad built together), and one of my all time favourite planes was the Cherry glider even if it did have a fuselage that went brittle in the cold. Lets hope someone rescues the name at least...
Mar 04, 2013, 12:05 PM
1.21 Gigawatts!
Steph280's Avatar
I have a couple of HOTT telemetry modules for sale:
Mar 04, 2013, 12:49 PM
Registered User
Graupner is now: Graupner/SJ.

It has a new owner.
Mar 04, 2013, 12:50 PM
Registered User
Arxangel's Avatar
Originally Posted by skorp_jon
Graupner is now: Graupner/SJ.

It has a new owner.
What does the SJ stand for?

Could it be the company that makes these chargers?;
Mar 04, 2013, 01:00 PM
BARCS 1901 BMFA S176 R-0200004
kiss the sky's Avatar
Originally Posted by Arxangel
What does the SJ stand for?

Although I don't doubt anything that I've read here, it would be good to see/hear a definitive statement from Graupner/SJPropo or anyone else who knows what the full situation is. I've personally invested quite heavily (in modelling terms) in the equipment over the last couple of years, get on well with the system and would wish to stick with it. But I guess we need to know what's going on.
Mar 04, 2013, 01:03 PM
Professional idiot
Yes. That is their direct sales site.

SJ Propo are the Korean company who actually made the Graupner HOTT radios in the first place. Buying Graupner gives them a name with a history to help in marketing to the Western markets.

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