hdeen

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Hi Guys would appreciate your comments on my predicament. I was flying my spacewalker when it suddenly dived while the plane was taking off. I know now it was not pilot error as I was on full up elevator. However after I rebuilt the plane I was flying it again and I was on base and it suddenly dived again. I recovered without crashing but I would like to know how I would go about trouble shooting the issue ? I dont want to throw the receiver away if it is a battery or servo issue. Please help! Thanks
Receiver HITEC electron 6
battery 1000 mah nicad
radio JR 2610
servos JR 537

jaka

Hi!
I would definitely replace that Hitec receiver!!
During my 30 years in this hobby I've seen a lot of Hitec receivers malfunctioning.
I'm also flying JR radios, never a problem since I started to use them in 1980. Why not use a JR receiver?

Regards!
Jan K
Sweden

Geistware

My Feedback: (16)

SOunds like the plane stalled.
If you fly too slow and the plane is properly balanced and set up, it will drop the nose when stalled and head for the ground!

redfox435cat

There are several factors that can lead to any event. to come out and say it was any one of them is imposable without physically handling and inspecting the model.
First thing is to asume everything with the model was fine. wheather it is or not.

My first though would be when you held full up elevator you stalled it, you simply never should be using full anything when landing or taking off. Even if it wasn't a full stall it will tip stall and become squirly very quickly. I can't even image how many times I've seen this and the person refuses to admit it was them.

Now asuming it was the model and not the pilot then some tests need to be ran.

1) either get a new or trusted battery and put it in the model or do a full cycle a couple times with the battery that is in it. Get a servo extension and plug it into an empty channel and hook a voltemeter to it. move your sticks around and see what kinda voltage drop you get with servo movment. My asumption here is is isn't the battery becuase a battery failure would lead to loss of all function not just one axis.
The reciever usually will again gitter on all channels with a radio hit, your model would abruptly change all axis as well as an engine blurp. It is very rare to have just one channel on a reciever fail, but anything can happen. If its the servo I say change it. If it really seams to be fine pull the servo off the elevator and put it on the engine. For me if any servo is gonna fail I'd prefer the engine servo fail. You can survive an engine dying or sticking to full, with anything like this I change all servo extension, and switch harness just for spite, that 10 bucks isn't worth the worrie, at least to me anyway

this is just sracting the surface with the obviouse. If the reciever has been in a crash before I always send them in for inspection even on my trash planes, ZAgi and stryker electrics. And I don't get any breaks being a dealer on it. But when you send the stuff in they replace the anntenna, change the capacitors and retune the equipment and do vibration tests. Most people would care less but it's the right thing to do. Also the issue of self interferance, metal part rubbing on metal parts that cuase interferance.

On a side note. even if it seems to work I've never trusted using differant brand of trasimiter and reciever. Especially JR. My exception to that is the FMA recivers which have active pulse shift function to change between negative and positive pulse

sbd-5

My Feedback: (4)

how fast was the plane flying when it dived?sure sounds like a stall.how much elevatoe throw do you have at full?sure sounds like a stall both incidents occurred at airspeeds that were decreasing.

matus777

hdeen... check your elevator pushrods...i flew the same plane for a fellow at our field and was barely able to get it back for a landing due to very soft elevator pushrod system/setup. Try holding the elevator while you operate the TX stick and see what happens....any type of airload would neutralize the elevator and cause a nose down condition...it might not be your specific problem but it's sure easy to check...he set it according to the manual....don't just rely on a visual control check!

hdeen

deep thanks to all for your comments. I guess I was not explicit enough but for the record it wasnt a stall. The plane hit the ground on take off speed. Picture on take of suddenly hitting down elevator just meters off the ground. Thats what it was like. I am going to go with redfox and jaka's comments and I think it could be the battery which I will test (its a glow plane by the way ) or the hitec rx which has given me stellar service so far now possibly malfunctioning. It is sad 'cos it is lovely plane to fly and now it flies like a brick (after my rebuild). I guess I need a replacement rx + plane
cheers everyone

britbrat

Does it pass an engine-on range check? If so, it is not likely to be the Rx. I have found Hitec Rx equipment to be highly reliable & resistant to crash damage.

Did the plane cartwheel at some time? Did you do any repairs to the wings, or were they damaged at some time? Ditto for the horizontal tail.

If there is internal damage to a wing, sometimes it can twist as the airspeed rises & cause severe washout, resulting in a sudden diving roll. I have seen this a couple of times on LT-40's that had been knocked about.

Another possibility is a cracked spar in the horizontal tail that lets the tail twist up at the LE -- resulting in a sharp dive.

hdeen

Cheers Britbat,
yes passed the range check, the plane had never been in a crash and was in excellent condition. On both days where the symptoms in question revealed, the days were absolutley perfect. Sydney is a beautiful place to be in winter (sunshine, not much wind and nice temps). I have to think it is radio\electronics\battery related.
I am going to fly it again with another rx this weekend to isolate the hitec rx and follow the advice given and check the battery performance.
I had seen a similar performance (but more deadly) when someone switched a tx on the same frequency. Didnt happen to me then and on these occassions I was the only person on my frequency.

hdeen

Thought I would conclude this thread to all kind enough to contribute or interested to read. The culprit? Loose connection from the switch harness to the rx. It was half out and possibly working intermittently. It was not apparent as I had wrapped the rx with foam. Anyway had a very successful day today and thought I would share this if anyone else comes across the same issue. It should be included in your trouble shooting scenario.

Happy Flying!

rrragmanliam

My Feedback: (1)

Hi Hdeen,

I'm glad you got it figured out. I had a feeling it wasn't the RX. I've used Hitec recivers for a very long time, know guy's who have also and haven't ever had a glich. I'm not saying it can't happen but for one guy to see "alot of malfunctioning Hitec recievers" is truly astounding as I've seen none. Jaka's experience with the Hitec recivers doesn't ring true with me. Fly your Hitec gear with confidence it's good gear!


Darren

pt19 flyer

My Feedback: (1)

hi hdeen

I have been using hitec equipment with absolutely no problem. it is good gear and excellent service if you ever have a problem. I have an eclipse and an earlier tx and about 5 receivers and all do and have worked perfectly.

it sounds like you are stalling the plane, when coming in for a landing make sure you keep the nose of the plane below the tail as you view it. on take off just be sure you reach flying speed before giving any up elevator. you should never have to use full elevator throw on take off or landings. think this is your problem.

good luck and happy flying

pt19 flyer