Ernst Grundmann

We have done some measurements. The battery is a 5 Sub-C cell XCell 2000mAh NiMH battery. They have been used only for one season and are in very good condition; we tested them. The current drawn from the battery with those four servos connected and moving is no more than 0,7A continues, and 3A peaks. This is when the servos stop and go directly in the opposite direction. The servos are not connected to anything, so they don't have to "work." The servos are moved from full left to full right several times, and the battery voltage stays nice and constant. At the receiver, there is a very small drop of no more than 0,124V (124mV) when the peak current of 3A is drawn from the battery. Our conclusion is that the servos are of poor quality, and better servos are already ordered. Getting money back is a great hassle and not worth the effort. The servos will probably be used for unimportant things like opening the canopy. Again, thanks for all your ideas.

The battery as a possible cause was our first thought, but the battery is fully charged and in good condition. What is left are the servos themselves. They cost about £18 each, so they were rather cheap. That may very well be the issue here. Thank you for your input. I think my friend should buy new and better servos. Indeed, a crash is much more expensieve.

Dear people. First, I wish you a very good new year. As the "electronics man" of our club most members come to me if they have problems with their electronics. We have a strange problem I want to ask for your help with. A club member and good friend of mine is building a scale P51. For the ailerons and the flaps, he bought four new digital servos. They have a blue aluminum case with a black plastic bottom and top. On the label is printed: 30Kg SERVO DC 4.8 ~ 7.4V Deao DSSERVO DIGITAL SERVO. They are connected to a Futaba R7008SB receiver, and a Futaba T16 transmitter is used. When he moves the servos from full left to full right a couple of times, all seems to work correctly. But when he stops moving them, the servos don’t go to the rest position in one go. They move until about ¼ of the rest position and then go to the rest position in 4 or 5 steps. The ailerons and the flaps are not yet connected; the servo’s have only the servo arm mounted. All four servos show this effect. We think it is not the transmitter and/or the receiver because if other servos (S3001) are used, they work normally. Does anybody recognize this effect and have a solution for it? We would be very grateful for any help.

In our club there is also a group of people that do exactly the same thing. One of our members has designed and made several singel channel transmitters that use normal 2.4GHz transmitter modules and receivers. It is great to see this working perfectly and to see how model airplanes where controlled in the fifties and sixties. But this is not what we have in mind. As I wrote we really have checked if it was possible to build a transmitter and receiver exactly the same as used in 1954. The first problem we encountered was getting the important parts like the tubes and the reeds. This proved quite difficult but there was somebody who claimed he could find or make the tubes but for a price! How much I don't (want to) know. The next problem was getting a licence to use it. Normally it is not allowed to use a home build radio control transmitter here in The Netherlands. Only in special cases one might get a licence. The next and biggest problem is the very poor selectivity of the receiver and the very large bandwidth the transmitter uses. One transmitter would almost completely "swamp" the whole frequency band used. Because of this the chances we will get permission to use it are very close to zero. Al in al we use 35MHz Futaba equipment that has proven to be very reliable. Flying with only rudder and elevator trim would complement this project but not every member of our club can control a model this way. Maybe I should explain more about what we do and how we do it but this will go very much off-topic! Should I start a new topic for this in a more suitable part of this forum?

Hello, Reading the articles you showed me makes me a bit worried. There are quite some differences between the articles. In one article the wingspan is 6 feet, in the other it is 7 feet. In one article the tanks held 24 ounces in total. In an other article is it 3 pints, a lot more! In one article the start was good and the model climbed away in a steady climb. In an other article it just barely got in the air and sort of nosedived over the cliff edge. Sid Allen needed all his skills to keep the aircraft under control. There are more differences but I can not write them all down here. It seems to me that the writers (journalists?) had some problems with telling the real story, this is still the case now a days I am afraid. This makes it more difficult for us to build the model as much as possible the same as the model that crossed the channel. Thanks so far and if there is something you want to know please ask. I will keep an eye on this forum and if I need help again I will put the question(s) here hoping you can help me as you have done the last couple of days. Also I will keep you informed about the progress of our project. Edited By Ernst Grundmann on 04/06/2020 21:46:24 Edited By Ernst Grundmann on 04/06/2020 21:47:47

@Brokenenglish. Our reference is the model that crossed the channel. As far as I knew this was the original model but thanks to you all I have tons more info and I now know this was not the original model. Our thought was that this model was purposely designed for the flight across the channel and I thought so too. This put things in an other perspective and also makes things a lot more difficult. Obvious things like the tail skid and some other small outside things will be easy to duplicate. But details inside and other changes that are not documented can not or very difficult be copied. Your video is not visibel for me the "owner" must give me permission to view it. ????   @Phil Green. We have been thinking about an original transmitter and receiver. These are no longer available but I am pretty sure that we have enough electronics people in our club that will be able to build a working transmitter and receiver. That is if we still can get the parts we need, that can be a problem. But there is a bigger problem with this old equipment. As I mentioned before there are much, much, very much more radio signals in the air right now. The receiver is absolutely not selective enough to differentiate between all these signals. The receiver will go crazy en control over the aircraft will be very tricky. This is why we will use 35MHz equipment. Maybe later I can explain more about why we choose this frequency about 4 years ago for our escapades. Also I want to apologize for my English. This is not my native language so sometimes I will make mistakes. Edited By Ernst Grundmann on 04/06/2020 14:06:49

The original model that crossed the channel had a tail skid. The almost mid fuselage weel is a change that has been made later. It is possible that the tail skid was only on the channel crossing model because it is lighter than a weel and weight was (is?) a very big issue here. But you are right it is late and I will be back tomorrow afternoon. Thanks for your help so far, we appreciatie it very much.

The discrepancies are the rudder, the tail skid, the nose of the model and some other minor changes. Just to be sure I downloaded the drawing from Outerzone and it does differ from the drawing I already have. The nose and some other changes are marked on this drawing so I can change my drawing accordingly. But the rudder still remains and I do not know what the original wingspan was. As I wrote before I found 4 different sizes. It is our intention to build the model as close to the original as we can. Some changes may be necessary but we want to avoid this if we can.

Thanks for your info. We have the Outerzone plans, these are our starting point. One of our members has the model from a Ben Buckle kit, he can not find the plans any more but there are to many discrepancies with the original model. We really hope that there are some people that know about the original model.

Hello, My name is Ernst Grundmann and I am from The Netherlands. As a member of a group of model air plane builders and pilots I want to ask you some things. Our group goes by the name "The First Aviators" because we want to build an fly very early aircraft and aircraft used for records or special events. We have already made some special flights and we want to make an other special flight. We want to repeat the first flight of a radio controlled model air plane across the English channel. This is not completely new for us because we have already flown across the channel twice before in 2018. This was with a very old model build by one of our members about 40 years ago. The old 26cc Olson engine on it did not run reliable any more and was lacking power. It was replaced by a much more modern Zenoah 23cc. Enough about this. We are planning to make the flight with the same model as the first flight, the Radio Queen. We want the model to be as much as possible like the original model. We already have a good running ED Hunter 3.46cc Diesel. Here is my first question: On the engine they used a special exhaust stack to make sure as much as possible of the oily stuff gets outside the model. You can see it on some old photo's and it is mentioned in some articles I have read. Does anybody know how this exhaust stack is made? Are there photo's or a drawing of this somewhere? Unfortunately using an original radio control set is not possible. First of all it is no longer available so we would have to build it ourselves. Not impossible, there are some electronic engineers among our members. The biggest problem is that there are so many other radio signals in the air right now. This will cause far to much interference to make a safe flight possible. We will use “modern” 35MHz equipment. It is my task to make good drawings so we can build this model and this proves to be more work than I thought. The drawings available on the internet are a good starting point but there are quite some discrepancies with the original model. Some things can be seen on the few old pictures I have found. Some other things are still on the drawings I have but an important thing is not clear to me. What was the original wingspan? I have seen 6’, 6’10”, 7’ and also 8’. Looking at the few pictures on the net I think 8’ is too much but 7’ could be just right. This would make the spaces between the ribs just big enough to fit 2 tanks, 1 in each wing, holding about 12 once each. Exactly what the original model had. Is there somebody who has more info for us? Any info is welcome! We are planning to make the flight next year. Edited By Steve Hargreaves - Moderator on 03/06/2020 14:13:48