Real Radial Sound

[modeldesigns]

Hi Tahustvedt and all,

LOL, yes, warbirds are my favourite. I am following your thread on the the Spitfire build on E Zone and the additional detail you have added looks very impressive. Good luck with the project.

On the Saturday just past i finally managed to bring everything together and the Corsair has now flown with a radial engine sound simulation. I owe a very big THANKS to John for all his expertise and encouragement and to Gordon for braving the cold and getting the video. You can see the first flight off here:

http://www.putfile.com/modeldesigns

More video is to follow soon.

Assuming it is possible, in my opinion the sound volume needs to be reversed i.e. the high power engine sound volume level should replace the engine idle sound volume level and vice/versa. Even as it is, i can see the potential for realism in flight. In the part of the recording showing the cowl coming off, when you hear the normal two stroke engines in the background, it really brings it home. And don't forget, if required, the model can be flown without any sound by simply not turning the speaker circuit on.

The flying weight of the Corsair is now 10-1/4lb compared to its usual 9lb. I am flying the model a little too fast to be realistic but i wanted to be safe operating at this higher wing loading and i am sure with practice i can cruise around at a lower airspeed. The real answer, though, is to now place the same sound hardware in a larger airframe...and add brakes and smoke on startup!

Keep up the good work everyone, IT IS going to happen!

Pete.

ps. The horrible scraping noise when the model is taxiing is the hard plastic tail wheel. I replace the supplied soft foam ones as they tend to flatten off with time but for operating off of tarmac with sound, i need to change them back.

[Johnr]

Well done Pete,
That really is excellent progress with super flying (as usual), and every flight that is managed without problems is another to prove the reliability and airworthiness of the system.

Next year reserve your seat at the Baftas Gordon for the super video clip, and as for the acceptance speech for the best director, I guess you had better start jotting down some notes!

Thanks for the information about the programming lead Thausdvedt, I think I will have to try a lead to see if that helps with changing some options if required.

Richard are you still out there sunning yourself in Brissy? How about some more pictures of your Corsair build with that fantastic flying field?

All the best,

John

[Gordon]

Hi Guys

This project is getting better and better!

I must say that I'm bitterly disappointed with the amount of wind noise on the video. I bought an external directional mike costing 100 quid for the camcorder with the intention of cutting out camera drive noise, and enhancing sound reception from a distance. I only found out after watching the videos the day after we flew that adding the external mike switches off the wind cancellation in the camcorder. There was next to no wind at all, but what little there was sounds like a gale on the video. So much for Canon quality!

So it looks as if the external mike will stay in its box and I'll have to put up with motor noise.

Even so, it doesn't detract from the success of the sound project at all. Pete's super-smooth flying was a joy to video, and the engine sound was fantastic.

To get the best effect on your PC, turn up the volumes to max on the speakers and sound card. Then control the sound level output by left-click and hold on the putfile volume slider, decreasing volume when the plane is on the ground, and increasing it to max when it's in the air.

Cheers

Gordon

[Bigplumbs]

Hey Pete now you have got me reading these boards as well

www.densplanes.co.uk

[modeldesigns]

Hi Bigplumbs,

That's the trouble, it's too easy to spend ALL your time on here and not get on with the practical!

Good that we can share ideas though.

Pete.

[Bigplumbs]

I know but I am waiting for some glue to dry on my H9 Mustang...... But shush I can't mention it in this forum................. You know why.

[modeldesigns]

Hi Bigplumbs,

IC(!), i won't tell anyone then...

Pete.

[old git]

Hi all,

I last built a model in the 70s and now retired am back to the fold. Things have changed beyond all recognition. I thought I had kept in touch with modelling by buying the occasional magazine and now retired for a few years, decided to build again. I think the video of the Corsair is a tour de force, so many different branches of technology coming together to make a film that doesn't need special effects to look real. Congratulations to all involved.

I previously made a comment about using the airframe (wing skin perhaps) as a substitute speaker cone and thereby saving weight but maybe I was misunderstood. I am among the many, being without special knowledge of the subject of speaker design but would like to understand why the idea is not practical if that is the case.

old git

Aren't wheels great?

No matter how badly you kill an aircraft, the wheels are always okay!

(With thanks to Andy Ross)

[Johnr]

Hello Andy,
It has been suggested before to force the wing skin to vibrate and use that as the sounding board instead of the speaker. In fact there are some commercial (NXU I think) flat board heavy speakers that use this same method. This principle does happen on the model as a reaction to the speaker pulsing the air in the wing. If just a solenoid were used then I think it could be used to produce some sound, but probabaly not enough, and probably not the right quality of sound. When I see how hard these poor little 4" speakers are working, and the flexing amplitude of the cone to move the air to make the sound, I think it would be difficult to get the wing skin to compete in a similar fashion. I hope someone proves me wrong though!

Hello Dennis, I hope you wash your hands before coming on this site. We don't want methanol streaks here!

All the best,

John

All the best,

John

[modeldesigns]

Hi Everyone,

I have now posted a video of the Corsair's 2nd flight with sound. Thanks once again to Gordon for the excellent film work.

http://www.putfile.com/modeldesigns

I must have set the props tick over a little higher this time since i got the model moving on low idle sound. In 'Auto Start' mode, which is what i have my sound module on, the sound shuts down after 20s of idle and in the film you can here the sound 'cough' as i just caught it before i turned into wind for the take off. That would have sent a chill through any full size pilot as he was about to trust his life on the motor in front of him!

The Axi 4130/16 on TP 6Ah 6S ProLites and a 16" Pattern prop in the calm air gave even a 15% overweight Corsair a carrier take off - very impressive. The total filming time included 5mins of warbird flying and i used 2.5Ah from the flight cells and 0.4Ah from the 1600mAh 3S LiPo amplifier battery. I should still have enough capacity for a safe 10min warbird flight, even at the higer flying weight.

I must find my Corsair manual and read-up on stall turns...room for improvement there! LOL.

Pete.

[inedesca]

Could anyone rather design a whistle or siren which might resemeble the engines sound?
I mean, maybe some kind of whistle taking advantage of wind speed and resonant chamber from the wing or fuselage.
Somebody which knows about whistle or siren design?

[eamrc]

AWESOME GUYS I JUST FOUND THIS THREAD !! I have got to have one of these for my B-17, also I am an audi buff from way back, I have a recording studio at my house, used to do P.A. work for concerts so this really stokes me to find ways to maximize our db output. Just sent an E-mail to get a sound module so I am in !

[Johnr]

Welcome Eamrc,
Your the sort of guy we need, and audio expert! We need top get more research done on small lightweight speakers that throw our large amounts of sound (100dBa+ at 1 metre). Can you suggest any improvements on the Visaton or Blaupunkt versions as mentioned in this thread? We really need more than 30w rms from less than 150 grammes.
All the best,
John

[CorsairJock]

Hi Guys (and Gals?),
I just started a thread in the RC Universe/ Warbird forum which contains links to the 2nd flight, and this thread, so 'traffic' might be picking up a little bit here.

Here is link to that thread:

http://www.rcuniverse.com/forum/m_3963203/tm.htm

That startup/ idle sound is GREAT, it that from the sound file that I sent in? I sure wish I could put one of these in my H-9 Corsair, but I can't afford it.

[Gordon]

Hi all
I shot the video. To get the best from the sound you should left click and hold the volume control, and set it to low for the idle and taxi phases, and open up the volume to full during take-off and leave it there during flight. Granted it's still not perfect, but it is better.

The main problem with the video is the wind noise. I'd fitted a $$$$ Canon DM50 shotgun mike to the Canon camcorder for the first time, thinking it would improve the sound. What I hadn't noticed in the instructions is that fitting the external mike shuts off the wind cancellation feature, which is why there's a lot of wind roar during the flight.

So the mike was a big waste of money as I bought it especially for this kind of filming

Cheers

Gordon

[modeldesigns]

Hi CorsairJock,

I do not know if the radial engine sound is from a sound file you sent in (to Benedini?). I am using it as it was supplied and it sounds fine to me.

Pete.

[Bil2]

Heck, man, do what we did as kids - put a playing card in the spokes...er..uh..prop. It'll sound just like the real thing. At least it did when I was seven. Ahhh, the Mickey Mantle rookie cards I wasted....Bil

[Bigplumbs]

Another option might be to play this type of sound in you MP3 player and fly with your earphones in lol

Click me

www.densplanes.co.uk

[watt_the?!]

absolutely awesome!!!..

is there any hope for us smaller scale modellers?...

Tim

[Johnr]

Hi Tim,
Yes there is hope for smaller scale models. I am working on that now. A standard Micro is fed into a new Benedini 35w 30v mono amplifier. This amplifier is driven from the flight pack so a separate (sometimes heavy) power source is not required. It is planned to drive a single 90mm diameter 6 oz gramme speaker. So the overall weight increase should not be 1lb but more like half that. The sound output may be a couple of dB less, but I think it has more chance of catching on if the payload is a little lighter.

Will keep you posted as the components are now ordered from Thomas Benedini and I will test the first amplifier to see how it performs.

When someone finds a speaker of 100grammes or less then it should be even better. There has to be one, but we haven't found it yet.

All the best,

John

[old git]

Hi John R,

I seem to remember from my distant interest in Hi Fi (I couldn't actually hear the difference) that speakers were loaded with concrete to allow the solenoid to work more effectively at driving the cone. Perhaps the frame of the speaker should be firmly attached to the heaviest components in the aircraft, battery maybe? This might enable more effort to be applied to the speaker cone with fewer mechanical losses.

[Bundy]

Hi All

I haven't yet caught up with all the postings in here yet but I must say a HUGE congratulations to all those involved in putting the Corsair video together! That is really inspiring stuff and shows what this thread is all about. The plane, the sound, the video and the flying are all suburb and one can't help thinking we are witnessing the dawn of a whole new direction of RC flight. Those little 2 strokes and even the biggier 'gassers' just don't cut it in the realism stakes anymore.

I've been locked away in my shed building the last few weeks. I tend to waste way too much time on the computer when I start on it so when there is serious building to do I stay away from it. Changing to the 6" speaker has meant starting the 81" Corsair from scratch. All has gone well and should have it on its wheels with sound and motor next week.

Biggest problem has been the canopy. Cosairs usually took off and landed with their canopies open to allow quick access for rescue crews on carriers so I want mine to be operational. Like many things it is easy to do but hard to do well. I've spent nearly two weeks on this alone and still not really happy yet.

Hope to post some pics next week but again CONGRATS to all those involved in making that video so believable.

Richard

[vax6335]

Originally Posted by CorsairJock

I sure wish I could put one of these in my H-9 Corsair, but I can't afford it.

CorsairJock,
Dang that's a neat picture of your plane! The Corsair is my all time favorite plane. It's nice to see so many on here.

[Johnr]

Hi Richard,
Welcome back!
We thought you had been sunning yourself or 'out bush'. Look forward to seeing the pics of the Corsair. I know it is a bit off topic, but how have you managed to do your sliding canopy? I have one to do in the next few months and would like to see how others do it. I have milled a slot out of square hollow plastic which is about 5mm square with a 1.7mm slot but haven't progressed any further than that at the moment.

The new 35w mono Benedini amplifier might be of interest to you if you are weight watching. Thomas is also working on a 50v (max) version which should be good for your 10s Lipos and not require a voltage regulator.

All the best,

John

[watt_the?!]

Originally Posted by Johnr

Hi Tim,
Yes there is hope for smaller scale models. I am working on that now. A standard Micro is fed into a new Benedini 35w 30v mono amplifier. This amplifier is driven from the flight pack so a separate (sometimes heavy) power source is not required. It is planned to drive a single 90mm diameter 6 oz gramme speaker. So the overall weight increase should not be 1lb but more like half that. The sound output may be a couple of dB less, but I think it has more chance of catching on if the payload is a little lighter.

Will keep you posted as the components are now ordered from Thomas Benedini and I will test the first amplifier to see how it performs.

When someone finds a speaker of 100grammes or less then it should be even better. There has to be one, but we haven't found it yet.

All the best,

John

this is so good!!...does it need to be 90mm?

Tim