Turbinac

Frank,

Sounds like the 1" internal diameter fibreglass tubing that runs through the boom is a tiny bit off horizontal line.

Use some 3/4" or similar dowel with some fine or medium glasspaper glued round it to gently ease open the inside top of the fibreglass on the wing end and the bottom of the tube on the fuselage end. This will allow the boom to lie right up against the centre section and also against the outer wing panel rib.

Do it gently step by step, trying it until it fits. Problem solved in five minutes. You'll probably find that removing just a few thou. each end as described will do it. Do not try to rub a groove right through. If you do it carefully the small boom tube will still be a snug fit halfway through, so the carbon fibre spar will locate the boom right where it should be.

Alan

PS. You can always Email me at [email protected] if you need further help.

funflyerf4

My Feedback: (6)

Hey Alan you lied, it took 10 min. and problem solvedThanks that was it.It should be back in the air on Sunday.

hendrix

My Feedback: (2)

I want to ask anyone in this forum with enough flights on the Boomerang intro what is the smallest servo he would fit to the elevator
and ailerons regardless of price.
Of course i know that this is only a recommendation and what ever i decide to do will be my responsibility.
I just want to hear everybody's opinion about that because i am trying to remove weight from the tail section.
Thank you in advance.
Chris

kwb

I presume you mean rudders and not ailerons if you want to reduce tail weight. I know somebody that has used HS85 in the rudders for several years without any issued but you will have to modify the servo housing to accept for the smaller servo (pack it out).

Ali has flown the boomerang on std cheap servos I believe so maybe he could give some advice. I have used full size servos in my rudders and a full size digital JR for the elevator and my model balances without and lead in the nose.

In case it helps with servo selection I have just used some JR 361 digital servos in my Savex L39 and these are HS85 size but 5 kg torque.

KC36330

JR DS3421 are 1.04 oz, they are on every surface of my A-4s but flaps, never had a problem with them and wouldn't hesitate to recommend them on the ail/ele/rud on any size boomer.

hendrix

My Feedback: (2)

Hi.
I already have mini servos at the rudders (waypoint 150mg 4kg) and they work great. Please excuse me for not being more precise, it is my fault.
They are cheap servos but i have used them extensively and i consider them to be excellent servos.
I am trying to save all the weight i can so i have already replaced the 4 screws in the elevator with aluminum ones and believe it or not
the 10 grams i saved from the tail was more than evident when balancing the plane.
I use a P80 (basically i use a KJ66) which is rather heavy at 1450g so i am forced to use 600g of batteries right in the nose of the plane (after the nose landing gear).
I think i will try one of those as my elevator servo is 55g, 13kg of torque which after many flights it looks to me that it is an overkill.
I don't want to buy a cheap servo only a good lighter than 40g servo.
Chris

kwb

[/quote]

In case it helps with servo selection I have just used some JR 361 digital servos in my Savex L39 and these are HS85 size but 5 kg torque.
[/quote]

I have just had a look on the JR website and I was wrong these servos are 3.8 not 5 kg.cm

Gary Arthur

My Feedback: (29)

I had a little air to ground incident with my first boomer.

Now it is time for round two.

swissflyer

WOW awesome colors!!!



decals or paint?

hendrix

My Feedback: (2)

If ~4kg of torque is enough then i am lucky because there are fine servos out there in this torque range.
My judjement is that a digital servo of 4kg of torque is about right for the Boomerang intro as the digital servos have tremendous holding power
and i guess the possibility of aerodynamic surface fluttering can be avoided.
Chris

Gary Arthur

My Feedback: (29)

All done with covering

hendrix

My Feedback: (2)

Looking at your very good work with covering reminds me that i am probably the world's worst man when covering is needed[&o]
All the times i tried to cover something i failed miserably.
Chris

ViperOneNL

Hi,

Yesterday I flew my boomer intro, my speed indicator clocked 173 MPH, now I dont know how reliable the JetCat speed sensor is, but I guess this is a respectable speed for an P70 powered intro

Outside temp might have helped a bit it was 2 degrees below freezing .....

Cheers,

Mick.

KC36330

I'd guess you either have the sensor mounted inside the dynamic pressure of the fuselage or you haven't properly calibrated it, even with P-70 you'll have a hard time hitting 173mph with the drag of the intro.

ViperOneNL

KC36330,

Exactly my thought:

ok for mounting, I use the BVM speedsensor mount, this will place the speedsensor about 2 inch outside the fusulage, the sensor is mounted in the first compartment in front of the fuel cell, in between the striping. (on the side of the plane)

As for calibrating the speedsensor ... how do you do that?

Cheers,

Mick.

KC36330

you use air tubing and water to calibrate it, your instruction sheet should have it outlined in details. the BVM stand off should have you mounted properly.

Gary Arthur

My Feedback: (29)

One thing to mention that may throw off the speed sensor is that the boomer intro can create a low pressure area inside the fuse. If your static pressure is from inside the fuse, the final reading may vary. Many people add extra openings into the canopy area. Even with the extra openings, I am sure the area inside would have a slight low pressure.

highhorse

My Feedback: (2)

I would think that finding a neutral location for the static port would be the toughest part...and I wouldn't know how to pick a spot.

ViperOneNL

Hi,

On the Jetcat Speedsensor the static ports are on the same pitot tube, i.e. dynamic presure from an opening in the front, static presure from 4 openings half way in the side of the tube.

As for calibrating, I just read the JetCat speadsensor manual again, and there is no way or need ???? to calibrate the sensor. It will calculate the speed using the pressure difference between the static and the dynamic port AND the air temperature .....

It might be not accurate to the mile, but would the calculated speed be that off? I dont know to be honest.

Cheers,

Mick.

KC36330

all pitot/static systems are universal on the testing method. you seal the static port so it can't leak (no duck tape doesn't work) and then connect a tube over the pitot (thats also sealed and doesn't leak). this tube is lengthy so that it has a few coils that are well below the pitot tube and these coils are filled with water (coils laying on the ground on full scale aircraft, having your jet sitting on a table with the tube on the floor for a model). as you raise the tube on the end not connected to the pitot tube........by picking up the tube for every XX inches you raise the water level on the open end you should get XX mph/knots of indicated air speed. just have the water levels enough below the pitot tube you don't force water back into the lines (although we have drains on full scale systems for moisture removal)

B58

My Feedback: (43)

Wow, in over 30 years in the full scale and drone business, I never used a water tube. Guess you could to replace the pricey little pitot/static tester, but don't think you could certify the system. Never thought of that way to do it. Bob

ViperOneNL

hi,

Ok now I have a way to put controlled pressure on the dynamic opening, BUT still dont have any way to adjust the jetcat readings, there are no adjustment menus, or any other way to adjust the reading, so other than knowing it is right or wrong, and recalculate the reading (assuming the calculation factor does not change with temperature difference) after each flight is also somewhat silly.

Dont get me wrong, I appreciate the suggestion and explenation, but it is not practical for everyday use ..... at least not to me

Cheers,

Mick.

digitech

My Feedback: (10)

one needs to read the manual[:-]

especialy page 56
http://www.jetcat.de/downloads/jetcatgerecuv5neu.pdf

weird thing is they left the calibration bit out of the US manual
if anyone needs some translation i can read it..

KC36330

you didn't happen to work for the Department of Army I'm guessing I'd never had the pleasure of the digital system till i transfered to the Apache and Longbow program in the late 90s and on the CH-47s they still used the hand pump/vacuum pump for airspeed indicator and barometric altimeter testing/leak test.

KC36330

it isnt the temp (unless you are having iceing issues on the pitot tube) so much the barometric pressure.