G&L 1/5 DHC chipmunk - diary of a build.
09-06-2014, 12:45 PM
#676
Banned
Blue text inserted by Zor.
I know that the antennas are to be at 90 degrees of each other.
For readers . . . Antennas can be at 90 deg in the same plane.
The best is to be at 90 deg in two planes that are also at 90 deg.
I have always ignored that and just install the receiver in the fuselage. I have never had a problem and with Futaba I feel confident.
When flying aerobatics the model is usually well within a strong radiated field.
It has to be close enough to clearly see its attitude and response to controls.
I will do a series of range testing and so on. I did not have the room to have both antennas come all the way out and at 90 digress.
The two antennas are already all the way out. We can see the ends of the coaxial lines outside the fuselage. All that is needed is their relative orientation. Where they are coming out is fine.
Futaba for carbon fiber recommends just the tips of the antennas to be out side of the fuselage so we will see. The second receiver will have the antennas in the second pilots cockpit.
Not only the tips of the antennas have to be out; the whole antennas ( 1/4 wave length; a bit more than 1 ( one ) inch ) has to be out. They are all out in the pictures. The coaxial lines ( transmission lines ) can be inside since their shields are grounded.
TB
I will gladly remove this post if you feel inappropriate.
I am just thinking about all the readers out there.
The antennas do not originate at the receiver case; they are at the ends of the coaxial transmission lines.
Zor
Last edited by Zor; 09-06-2014 at 12:55 PM. Reason: Fix noted typos.
09-06-2014, 01:09 PM
#677
Rivets
I am getting a start on the right bottom half of the wing.
I needed more rivets so I asked Chad to print up some white ones.
This should cover better then the gray or silver. I am not doing weathering so I don't need silver.
With this Klass Kote primer the rivets apply much better. I haven't had one pull up yet. It was a struggle at times on the fuselage.
The stitching should do better to. On the elevator and ruder some of the ends of the stitching lifted when I was painting.
Should go pretty quick and far as the rivets go, the stitching and glue drops will take a bit more time.
TB
I am getting a start on the right bottom half of the wing.
I needed more rivets so I asked Chad to print up some white ones.
This should cover better then the gray or silver. I am not doing weathering so I don't need silver.
With this Klass Kote primer the rivets apply much better. I haven't had one pull up yet. It was a struggle at times on the fuselage.
The stitching should do better to. On the elevator and ruder some of the ends of the stitching lifted when I was painting.
Should go pretty quick and far as the rivets go, the stitching and glue drops will take a bit more time.
TB
09-06-2014, 06:41 PM
#679
Banned
Last post about antennas
I do not intend to get this wonderful thread out of topic but I thought that after all this wonderful work you are doing ( including rivets and stitches ) that you would wish the best and most reliable radio link with your airplane.
From where the antennas are coming out of the fuselage _ _ _ imagine two flat vertical cardboard making a 45 degrees angle with the longitudinal axis of the fuselage so the two form a 90 deg angle to each other.
You can bend the antennas in the imaginary flat face of these cardboard at about 45 deg toward the tail.
That will make the two antennas 90 deg from each other and in two directions to take advantage of the polarity of the radiated field from your transmitter.
Trying to qualify my competence in this subject _ _ _
Graduated in electronics at Montreal technical School ( a four year course ).
Two years as chief instructor for Radio College of Canada in Montreal, QC.
Twenty years with Radio Corporation of America as application engineer.
Introduced 'General Radio Service in Canada' ( so called 'Citizen's band) while with RCA.
Amateur radio operator ( so called Ham ) since 1946 and still active.
Attached pics of some of my reference on hand.
I will not post more on antennas unless you have some specific questions.
I am just hoping that your most beautiful and detailed model will have the best radio link possible.
Best 2 U,
Zor
09-07-2014, 02:23 AM
#681
The nice thing about Chad's rivets is the flexibility. Any color, any size, any spacing. I chose white so the yellow would cover.
I am learning a lot about finishing. These rivets will simulate raised rivets if you paint them heavy. I think making them look like flush rivets is harder and requires a lighter coat of paint.
I love your aluminum rivets, just cant see me doing 30k of those
The vinyl rivets are so easy it not even funny. 
TB
09-07-2014, 02:33 AM
#682
So while we are talking about rivets. I have heard from past Top Gun competitors that you cant compete (with the big boys) in Top Gun using vinyl rivets. And that your panel lines need to be bigger then scale. It has to do with how they see them, I have been told.
I disagree with this and feel that a plane should look as scale as it can even up close and that if you cant see the detail from far away then you are doing your job. I don't know how they judge these competition or who is judging them. Vinyl rivets and panel lines done right in my opinion look more scale then some of the other old school techniques.
Anyways viva sports scale
TB
I disagree with this and feel that a plane should look as scale as it can even up close and that if you cant see the detail from far away then you are doing your job. I don't know how they judge these competition or who is judging them. Vinyl rivets and panel lines done right in my opinion look more scale then some of the other old school techniques.
Anyways viva sports scale
TB
09-07-2014, 07:54 AM
#685
Not to take away from your build Tony but what Zor said about antenna leads is not the norm for 2.4 reception every since it's inception. Also with the satelite antennas on the 2.4 systems sometimes as many as 3 or 4 located throught the plane it's almost impossible not to get the signals. Air waves will pass through almost anything including our own bodies, ezcluding lead and our planes can hardly create a shield to prevent radio waves from entering their bodies. I guess what I'm saying is that directional antennas do pick up signals better and that is one of the reasons for the satelite antennas on the 2.4 systems because the plane is never in direct alignment to the transmitter. In all, whats the point of a given portion of antennas sticking out of the plane at any point when a good majority of the time it's not going to be facing the transmitter anyway.
Probably not the place to discuss this, it's very debatable to say the least.
Leroy
Probably not the place to discuss this, it's very debatable to say the least.
Leroy
09-07-2014, 08:18 AM
#686
Join Date: Sep 2006
Location: The Sunshine state, when it's not raining!
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Tony, install your recievers and don't worry about it. I have numerous wrapped in aluminum, which is deadly by some, but things are fine. There are to many openings in our airframes for concern, and the directionality, by installation, always puts the antennas at different angles. Then add in the fact most Rx's have far more strength in signal than we can see to fly. Install them and keep on trucking I say.
09-07-2014, 10:45 AM
#687
Today I brought the chippie out to the field and my mentor gave her a look over. We did series of range tests. With the receiver and antennas as is I could run out as fare as I could with the 90 seconds I get to perform a range test, maybe 200' and everything worked.
The only time I would loos signal is if I put the transmitter behind my body. At 200' I am good. We did tests with the model in all different positions and I even turned the radio off and back on again under the range test mode and still had solid control.
We deemed it good and I will do a range test with the engine running before the test flights.
TB
The only time I would loos signal is if I put the transmitter behind my body. At 200' I am good. We did tests with the model in all different positions and I even turned the radio off and back on again under the range test mode and still had solid control.
We deemed it good and I will do a range test with the engine running before the test flights.
TB
09-07-2014, 10:51 AM
#688
Banned
Only to reply to Tony's question.
The attached sketch shows what I have in mind and what I would do.
I always show or talk about what I would do and I do not tell peoople what they should do.
I also provide reasons for my outlook.
We have read postings from fellows with obviously much more knowledge and experience than I have.
I suggest you do your own evaluation of the postings which should always be done anyway.
I think your Chipmunk will be a fast flier that could get pretty far very quickly and should have the best range regardless of its attitude ( not altitude ) to the incoming radio propagation.
Receivers can be fully shielded ( in grounded metal envelopes ) as long as the antenna(s) are out of the shield to pick up the induced signal. Considerations have to be given to the cooling of the receivers that I think should have free air circulation.
The sketch is in accordance with the work you already have done.
Ideally one antenna should be horizontal and the other vertical when the model is sitting on the ground.
Any more questions ?
Zor
Last edited by Zor; 09-07-2014 at 11:01 AM.
09-08-2014, 06:02 AM
#692
The Mornings progress.
Plugging away on the rivets, I got most of the rivets short of some details.
I will be doing the stitching next.
I hope to have the wing done today so I can start on the stencils tomorrow.
TB
Plugging away on the rivets, I got most of the rivets short of some details.
I will be doing the stitching next.
I hope to have the wing done today so I can start on the stencils tomorrow.
TB
Last edited by TonyBuilder; 09-08-2014 at 06:05 AM.
09-08-2014, 11:55 AM
#693
Wing rivets and stitching.
Got the top of the wing done with all rivets and stitching, short of the glue drops.
It is going to look nice with all that yellow paint on it
I will do the ailerons and flaps before I go to the bottom.
Break time!
TB
Got the top of the wing done with all rivets and stitching, short of the glue drops.
It is going to look nice with all that yellow paint on it
I will do the ailerons and flaps before I go to the bottom.
Break time!
TB
09-09-2014, 03:35 AM
#699
Morning progress.
Got the flaps all done and detailed.
The stepping area will get painted black during color overlay detailing.
Ailerons and the bottom of the wing stitching is left to do, then glue drops, should take me all day to do that.
TB
Got the flaps all done and detailed.
The stepping area will get painted black during color overlay detailing.
Ailerons and the bottom of the wing stitching is left to do, then glue drops, should take me all day to do that.
TB
09-09-2014, 05:43 AM
#700
Banned