Messages

1

Slope Soaring / Problem solved

« on: April 22, 2012, 15:41:35 PM »

Hi everyone,

Thanks for all the advice.  The source of my problem was the BBCodes were disabled.


Best regards,


Fergal

2

Slope Soaring / Pawel's Flying Wing

« on: April 21, 2012, 13:08:41 PM »

I am having problems getting photos to appear in posts.  Can anyone help.  I have tried to upload the photo to Glider Ireland and linking to the photo on Google+.  Neither works for me.

Fergal

3

Slope Soaring / Pawel's Flying Wing

« on: April 21, 2012, 13:01:21 PM »

Hi everyone,

Here is a photo of my latest project. It is a prototype flying wing made by Pawel. I have repaired it and did the covering.



Hope to get it finished this weekend.


Best regards,


Fergal

4

Radios / Telemetry Transmitters

« on: March 30, 2012, 19:04:07 PM »

Hi Alan,

Still working on Pawel's flying wing, making slow progress.  Are you going to get your powered model working and bring it up to the Curragh.


Fergal

5

Radios / Telemetry Transmitters

« on: March 30, 2012, 19:01:47 PM »

Hi Keith,

Don't forget KISS and the parsimony principle!


Fergal

6

Radios / Telemetry Transmitters

« on: March 28, 2012, 23:06:52 PM »

Hi Everyone,

I just got to the bottom the problem with Rx battery level warning.  As mentioned before, I was getting Rx battery low warnings after about 20 min flying time.  The problem has turned out to be a faulty on/off switch.

I have fitted a new switch and have had about 1.5 hours flying before a got a low level warning.  This is more realistic.

I appear to have had a bad contact and was probably switching off momentarily and dropping the voltage level.  Luckily, the plane did not switch off completely in the air.  It looks like the upgrade to M-Link system has paid for itself.

Best regards,

Fergal.

7

Radios / Telemetry Transmitters

« on: March 04, 2012, 19:22:59 PM »

Hi Alan,

Yes you are right, the Tx battery warning level should be set to about 7.2 V.  However, this is not the issue in question.  My Tx also displays the Rx battery voltage (M-Link telemetry) and the Tx also gives an audible warning if the Rx battery is low.  I start getting these warnings when the Rx battery still has 80 to 90% of its charge.

It would appear that although the warning is made by the Tx, the threshold is set in the Rx.  And this would make sense, as each model would have its own threshold, depending on the battery configuration and the current draw.  The other logical place for this setting would be in the model menu of the Tx.  However, there is no such setting there.

The solution is to get a MultiMate and use it to program the Rx with the appropriate settings.  The MultiMate got a good review in the February edition of RC Model World magazine.  Hopefully, this will do the trick.


Best regards,


Fergal

8

Radios / Telemetry Transmitters

« on: March 04, 2012, 18:13:08 PM »

Hi Everyone,

Thanks for all the help.  I am beginning to think the voltage threshold for the low Rx voltage error count is the same threshold for the audible warning on the Tx.  The default setting is 4.5 V, which on face value is a reasonable level.  However, I have done some tests on the ground, where I can focus on what is happening on the Tx screen.  I would appear that when there is an increased current draw, e.g., several servos moving fast, the voltage can momentarily drop by 0.3 to 0.4 V below its steady level.

When I am flying, it would appear the steady voltage first drops to about 4.8 V.  Then there is a momentary drop to the threshold voltage of 4.5 V.  I then level the plane, centre the sticks and when I look at the Tx screen I see 4.8 V.

If this is correct, then all I need to do is reduce the threshold voltage down to between 4.0 and 4.2 V.  The receiver will still work down to 3.5 V, so reducing the threshold to 4.0 V should not be problem.  I just need a MultiMate to program the receiver.


Best regards,


Fergal

9

Radios / Telemetry Transmitters

« on: March 03, 2012, 19:17:27 PM »

Hi Alan,

Thanks for the suggestions.  The manual for the M-Link Tx module (HFM4 M-Link)) states the following:

"If you use a telemetry-capable receiver, the actual voltage of the receiver power supply is displayed on the transmitter’s integral screen.  If the voltage falls below the set minimum value, an audible signal warns you that the battery is almost flat."

Section 12 of the same manual also states:

"The 2.4 GHz ISM band offers the facility to transmit model data
back to the transmitter. If you are using a telemetry-capable
M-LINK receiver, the actual voltage of the receiver power supply
will be displayed directly on the integral screen of your ROYAL-
evo, ROYALpro or ROYALpro M-LINK transmitter. If the battery
voltage falls below a certain threshold, the transmitter also emits
an audible signal to warn you that the receiver battery is almost
flat.

For more information on this feature, please refer to the opera-
ting instructions supplied with your telemetry-capable M-LINK
receiver."

The Tx module manual mentions "a certain threshold", but gives no indication of its level or how and where to adjust it.

The Rx manual in not any more informative either.

I have downloaded the MultMate manual and there is no sign of adjustment of the low Rx battery warning level.  The is a threshold voltage level for counting voltage errors and this is adjustable.  However, this is a different setting than the low voltage warning level.

There seems to be nothing in the main Tx manual in relation to telemetry or M-Link.

It is a bit of mystery how this feature is not well documented, given how well Multiplex generally document their products.  One would expect that this setting should be in the model set-up, as each model could have a different battery pack and therefore would require its own low voltage warning level.  Hopefully, this will be addressed in a future software upgrade.

Regards,

Fergal

10

Radios / Rx battery warning level

« on: February 27, 2012, 18:33:52 PM »

Hi Everyone,

I have a question about Multiplex M-Link receivers.  I have recently converted my Evo 9 from 35 MHz to 2.4 GHz.  By default I get the Rx battery voltage and battery connection quality by telemetry.  I get an audible warning on the Tx when the Rx battery reached 4.8 V.  I think this too for my 4 cell NiMH battery.  I have only used about 300 mAh out of a nominal capacity of 1700 mAh when I get the warning.

I have searched the Tx and the Rx manuals and web, but I cannot find where I can alter this warning level.  Does anyone know if this 4.8 V warning level can be changed and if so, how.


Best regards,


Fergal

11

Slope Soaring / C of G calculations

« on: October 03, 2011, 20:51:01 PM »

Hi John,

I have a spreadsheet that I have found to work very well for calculating the theoretical C of G.  It is based on calculations set out in Model Aircraft Aerodynamics by Martin Simons.   You need some measurements of the wing and tail, and their spacing.  The output is a graph of C of G against static margin.  Typically, the static margin should be between 5% and 15%.  15% should give a docile model that is easy to fly, while 5% will be very lively, ideal for aerobatics.

I could e-mail you the spreadsheet if you think it might be of help.


Best regards,


Fergal

12

Slope Soaring / Tuesday evening, 5 July

« on: July 04, 2011, 20:59:31 PM »

Hi Everyone,

Some nice southerly wind tomorrow, 25 km/h.  I am hoping the rain will have blown over by tomorrow evening.  I am packing my Typhoon into the car in the hope of heading straight to Lacken after work.  Hope the weather is kind and to see some of you there.

Regards,

Fergal

13

Slope Soaring / Flying at Lacken, Co. Wicklow

« on: June 24, 2011, 21:10:20 PM »

Hi Fred,

Sorry for not getting back sooner, I was out of the county for a few days.

Firstly, you will find the Lacken flying site at Lacken 53.13814 N, 6.441808 W.  Try Google maps.  It is a saddle between two hills and we fly off the west facing side.  There is a car park at the top of the saddle.

You get to Lacken form Blessington, about 10 km.  Again I suggest Google maps for details.

The flying site is a horse shoe shaped valley, generally facing WSW.  Winds ranging from NW all the way around to S can be accommodated by moving around the valley.  The main flying area, near the car park is ideal for the prevailing winds, W and SW.  Here there is a reasonably flat area out of the lift for landing.  You need to plan your landings in advance to avoid the odd rock.

For southerly winds you need to go back down the road and fly off the south facing side of the valley.  You fly from the side of the road.  There is no flat area here as the slope continues up the other side of the road, so landing is a bit more tricky here.  However, there are areas of long growth so you can usually find a nice place to land.

NW winds require a 15 minute walk across the heather to the far side of the valley.  This is the steepest slope and there can be nice flying here.  The is no flat area but the slope is covered in a thick covering of heather and cross wind landings are usually OK.

Here are some photos from my cheap camera phone.  I will get some better photos the next time I am at Lacken.

SW slope with the car park in the background:



NW slope with Pawel and Ed:



As regards Glencree, this is an east facing slope, suitable for NE to SE.  How do you manage to fly SW winds there?


Best regards,


Fergal

14

Slope Soaring / Flying at Lacken, Co. Wicklow

« on: June 18, 2011, 14:58:08 PM »

Hi Fred,

You missed nothing, the wind was modest and the lift was not not great.  It was bumpy with the occasional sink.

I was trying my RCRCM Typhoon with the CG a little further back.  I think I over cooked the change in CG.  It flew OK, however the Typhoon response to the turbulence was more extreme with the CG moved back.  Not nice flying.  I flew for about 10 minutes but then a sink forced me to land.  Of course, I would find that little hidden rock in the heather and undid by repair to the nose.

I taped it up, moved the CG back to where it was and got another 30 minutes flying with the Typhoon.  The wind dropped and it was time to try my floater.

So you missed nothing.

We must organise a fly-in at Lacken sometime.  Hopefully, when the wind is blowing strong from the west.

Best regards,

Fergal

15

Slope Soaring / Flying at Lacken, Co. Wicklow

« on: June 13, 2011, 20:24:22 PM »

Hi everyone,

I am planning to go flying at Lacken tomorrow (Tuesday 14 July) and plan to be there between 18:00 and 18:30.  The forecast is 20 km/h S and fine.  It looks as if we will be flying down the slope from the road, no walking.  What more could you ask for.  Hope to see some of you there.


Fergal