Advice Please

[Keith Berriman]

Hello Forum Members, just completed a Hyperion Cap232 and took for a maiden flight, just a little windy and a good take off but I struggled to get it down smoothly .. The CofG was set as instruction but it seems it wanted to lift its nose steeply when powering of for a glide in. Which way should I adjust the CofG to get a smoother glide I am thinking it could be slightly nose heavy. Any advice would be welcome

[Denis Watkins]

This size are fairly twitchy at the best of times, but don't just add forward C of G in excess

Double check that nothing is moving around inside

And check the C of G inverted as well as upright, that it is just forward, and don't add any weight for good luck.

I would balance dead level, but test whatever you do

[Keith Berriman]

Apologies for some lack of information its an Electric model 3S lipo with 330 watts of power

[Martin Harris - Moderator]

Check for excessive down thrust - if you trim for level flight at half throttle, does it pitch down as you open the throttle? If so, it's likely that the thrust line is wrong. Also, check the wing incidence is either zero or slightly positive.

[Ronaldo]

One reason could be that if the CG is correct you may have too much downthrust on the motor. If so then possibly you have trimmed it out for level flight with the power on, in which case it could cause the model to climb when you throttle down because the motor is no longer applying downthrust to keep the nose down in level flight.

[Ronaldo]

Lol. Martin got there before me. Good way to check it out in flight rc plane flyer.

[MattyB]

You could also try a power off dive test to check CG...

[Keith Berriman]

Hi All Just done a check on the set up with spirit level on wing thrust line and checked for zero incidence at rear and can see the down thrust in the motor set up, this is the set up in the manufactures light ply box arrangement. I can reset this on the way I mounted the motor to the ply box. as advised above one thing at a time. There looks to be a lot of right thrust as well

[Former Member]

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[Former Member]

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[Denis Watkins]

Hope this helps RC. I have one of these models and it flys great, But

I cut off the front box mount and fitted an ASP.21 IC motor

Onto a zero incidence ply bulkhead

With eventual fuel , tank and motor, this combo weighs 400grms,

There is no additional balance weight.

Main point being zero thrust line, and straight and level C of G, brought slightly forward

At take off by addition of fuel

Second point is that the model handles the difference in weight of 0 - 170 grms of fuel throughout the flight

Edited By Denis Watkins on 01/07/2017 21:13:46

[Keith Berriman]

Short update The kit instruction are saying its a 2007 model ( Red and White ) and mentions its improved from the 2006 model but not in any detail. I have reset the motor with no down thrust and doubled checked and there is a little right thrust, . rebuilt the undercarriage area and about to reassemble the wing on to the model to recheck on the CofG. It looks like mid week before I can get another test flight. Thank you for your inputs and will report back

[Keith Berriman]

Short update. Took a quick time out this afternoon and after recheck of all settings away we go but elevator control was still fierce short flight and got it down okay. Lowered the elevator down to 45 % and better control in a turn etc but coming into land still oversensitive on elevator tried moving battery but still not smooth enough for me. Will have to take a closer look at the wrap around elevator.

[Piers Bowlan]

Posted by RC Plane Flyer on 05/07/2017 17:08:25:

Short update. Took a quick time out this afternoon and after recheck of all settings away we go but elevator control was still fierce short flight and got it down okay. Lowered the elevator down to 45 % and better control in a turn etc but coming into land still oversensitive on elevator tried moving battery but still not smooth enough for me. Will have to take a closer look at the wrap around elevator.

When you say you 'lowered the elevator down to 45%' what are you meaning by this? 1) You reduced the expo setting to 45% (which is still huge, 20% expo is a reasonable figure) or 2) you reduced the deflection to 45% of the deflection that you originally had (whatever that might have been).

The manual states that the C of G should be 107mm from the LE but posters on RC groups have said 90mm is much better as 107 is too far back. The control throws are stated as Ailerons 24.5mm Elevator 33.5mm and Rudder 50.5mm MAX. So if you set dual rate at 60% of max as a starting point and see how it behaves.

[Keith Berriman]

Hello Piers. What I should have put in the wording was I reduced the rates down by 65% from the original movement as above. I fly most of my models at -30% have increased the expo on this one to -45% to try and eliminate the sensitivity. I am intrigued by the c of g and give that a try thanks for the information

[Piers Bowlan]

The information I supplied comes with a 'health warning' as my source was RC Groups, I don't have any personal experience with this model but it looks like a good-un. Have fun.

[Former Member]

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[Keith Berriman]

Still here asking questions My Apex motor comes in at 102 grams the Hacker as mentioned above 143 grams

A quick c of g re balance is looking like 170 grams under the motor pod assembly to get to he 90mm mark even with a heavy 2.2 lipo tucked well into the motor pod area. Will have a nice Latte Coffee and a rethink

[Denis Watkins]

Just a reminder RC, that my Cap carries 400grms in total up front, and does fly well

[Former Member]

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[Keith Berriman]

Short Update In between Latte's and painting outside I have managed to up rate the undercarriage, try a heavier 2650 Lipo well forward and now have a 93 mm C Of G. An alternative is back to my 2200 Lipo and 65 gm of lead on motor box

[Former Member]

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[Keith Berriman]

All things above tried with little success. Decided to revamp the elevator set up cut the end tips off reshaped them a little and re fixed them back on as a fixed tip. Bingo great landing's without oversensitive elevator and gentle glide in without the nose wanting to lift. Thanks to all who gave advise.