RCU Forums - crash

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- - crash (https://www.rcuniverse.com/forum/wildhare-r-c-support-355/2951081-crash.html)

[:@]after 16-20 fabulous flights
circling for final
approach lost all controll

[&o][&o][&o] Bummer! Batterys?

dont know had edge 540 28% beautiful
on 16-20 flight before take-off cheked batts
all green

mine just went in at 2.5 gallons i had the extra specail went hay wire 5 minutes into a flight on friday
i to had 7.3 volts with a one amp load was a great plane except for a wing drop prob

and im sorry for yours did the gear make it through the crash alright engine servos ect.

mine went like this

hey i didnt tell it to do that im going to land it now

2 seconds later "I dont Have it ".

50 seconds of fighting it ide get a tenth of a second of controll followed by 4 or 5 seconds of the pland going hay wire till it plowed in about 1 mile into the landfill

mine was flyin mint all day
then on last flight of day engine running
on final, rolled up and right and nosed dived into fence and ground,bent ulum wing tube,
shattered fuse,got to keep tail section hung it on wall.
servoes seem to b fine -got home stripped all the good stuff,
plugged servoes into reciever seams to b working cant range check alone
just gonna order a nutter plane for my da50 thought about switching hobbies,maybe
boats or cars?

landing geer good c/f tail and aluminum front landing gear

i just have to ask.. JR or Futaba equipment

MrKindNuggz:

please give us a post crash inspection report as to what went wrong with the ACFT

wat is post crash inspection report ,its my second plane,it flew 16 to 20 flights then crashed
lost everything motor running when it made contact with the ground excellent motor from D/A.
no radio control at last left turn comin in for landing crashed just missing many planes and humans.

if i knew wat went rong i would by anutter plane
u tell me w/w/w/

I was there & seen it all, helped em build this plane... after close inspection it more than likely was radio interferance do to the ignition module placement (was placed inside the motorbox) this is the only conclusion i can come to.
i have a H9 80" cap / DA 50 the module is placed on the outside of the motorbox & with antenne all the way down i can get over 75 yards away with no glitching, where as in the case of this hare the distance was dramatically shorter in the inital range check.

any other ideas?

Please post what gear was installed and where it was placed inside the plane, also if you can include pictures of the plane before the crash.....under the hatch, engine area...ect, Maybe we can help diagnose, or point you in the rite direction.

send the engine and ignition to DA for inspection and repair.

had my budda send my motor in today, and as far as picts dont know how to show pics, used 7ch/7cap trans 2-5945s on ail 2 on
elevator 1-5955 on rudder pull-pull ,1-3004 on throttle nun on choke ,no metal to metal connections strapped 6volt battery under servo
tray reciever above on top of servo tray antenna was drilled through the bulkhead out and down the belly couple inches from c/f rear
gear.ignition strapped to inside engine box onleft fire wall,ignition batt mounted outside, engine mounting box,on right side.
one JR H/D switch mounted on right side just behind canopy,same switch on ign, mounted in forward mounting hole on same side.
checked switches ,still working. 1024 pcm reciever ,running y harness for dual elev servoes.ran 6volt reg for reciever.

by the way thanks for the help

mstroh

signed MR KIND

Glad to help, What size and kind of battery? How many flights since it was charged? And if you can remember what the voltage was preflight?

If I read this correct only one flight battery, You might check for any bad connections between the battery switch and the receiver. also cycle the battery and verify the capacity.

Quote:

with antenne all the way down i can get over 75 yards away with no glitching, where as in the case of this hare the distance was dramatically shorter in the inital range check.

any other ideas?

That plane should have never been flown if it didn't range check within 10% of your plane. That was the first clue that someting was wrong.

TF

Were you using a PCM or PPM receiver?

Sorry for your loss. You were using a PCM RX, correct? Usually PCM solves most gas engine RF problems. It could have been the ignition module placement... What was the battery voltage? Is it possible someone turned on a radio on the same frequency?

In cases where the radio link is less than perfect, PCM can cause as many problems as it solves.

A regular FM receiver just takes the signal coming in, splits it into 8 streams (for an 8 channel radio) and sends the individual streams out to the 8 different servo channels.

If there is noise or an invalid servo signal, that also gets passed straight out to the servo. This is why, with a PPM (FM) radio you see the surfaces jump around when noise creeps in, they are just following the signal which sometimes is not valid.

With PCM there is processing involved at both ends, Tx and Rx. In the Tx, the 8 (or whatever) signals are combined into a frame where each servo position is represented digitally by a binary number. This is where the "PCM 1024" comes from, they use 10 bits to represent the servo's position so there are 1024 possible positions.

The values for all the channels are then packed into a frame (now nominally 80 bits of data for 8 x 10 bit channels) with a header and trailer, and at the end of the fram a check sum is appended that is calculated as the bits are transmitted.

When the receiver gets the frame, its internal processor recalculates the checksum of the received frame and compares it to what was received. IF they are equal the new values for each servo are transformed into the signal which is sent to each the servo.

But if the checksums do not match, the received frame is discarded and the values from the most recent good frame are retained. This is what is called going into a "hold", the receiver "holds" the last known commanded position that was without errors.

It gets more complicated with fail safe, but the basic strory here is that PCM covers up small errors that will show up with PPM. If you are having problems, you may not see them with PCM resulting in a mistaken idea that your radio is working great when it's not.

If you EVER have an insufficient range check, do not fly, and I recommend installing a PPM/FM receiver (temporarily) to help diagnose the problem. It's sort of like turning on a light, suddenly you can see all the problems that were hidden by the PCM Rx.

Once you get an acceptable range check with a PPM/FM receiver and with the engine running, now you can go back to the PCM and recheck the range.

It's worth the $60 (Hitec Supreme 8 channel FM) to keep one of these around just for checking out you plane, even if you never fly with it.

TF

You say you used a 6V regulator on a 6V batttery? If that's the case and you didn't use Li-ions or Li-polys, then the voltage to the RX probably went below the required threshold and you lost response out from the RX to all of the servos.

Tom, does this make sense to you (i.e. putting a 6V regulator on a 5-cell 6V NiCd or NiMH?

Bobby

A 6v nimh pack fully charged can go over 7v, so I guess it might make sense, but I never use one since I'd rather fly at 6.5v that 6.0 anyway. When the batteries go under 6v, (a) your batteriers are near dead, and (b) the regulator should just pass the low voltage through with a slight loss.

So I say what's the point?

It is staggering the number of people who buy stuff for their planes without either needing or understanding it.

TF

rctom:

It is staggering the number of people who buy stuff for their planes without either needing or understanding it.

Your 100% right, there are many of us who do not know the acual way how all this works,
I guess it's time for you to educate us on that subject, I'm sure it would be greatly appreciated.
and thanks, Tom