MPX Fire Arrow RC Trimaran Scale Test Model

Hi, my name is Doug Lord and I've joined this forum which I find very interesting. You all are doing very interesting things with RC Multihulls and I think it is just great. This is a link to a sort of summary page(post 811, page 55) of a model I'm building to test a new foil concept:
For some reason I can't leave the link? Anyway ,it's in the "Multihulls" section at boatdesign.net
I'll try to figure out out to leave a link and post a picture.
For "historical" reference, I designed built and produced the F3 trimaran foiler about 13 years ago..

Hi Doug,

welcom to our german forum.

Do you mean this link:

http://www.boatdesign.net/forums/mu...lf-righting-trimaran-test-model-36058-55.html

Best Regards

Jens

TomTest schrieb:

Hi Doug,

welcom to our german forum.

Do you mean this link:

http://www.boatdesign.net/forums/mu...lf-righting-trimaran-test-model-36058-55.html

Best Regards

Jens

Zum Vergrößern anklicken....

===========================
Yes, Jens-and thank you very much! I didn't get here in time but I wish all of you a Happy New Year! And good sailing and experiments!

Here is a picture of the boat and one of the wand system and a picture of the experimental ama foil(top). This is a test so we'll see if anything shows up....
Wow, it did show up!
For the wand system the whole assembly slides fore and aft to adjust the angle of incidence of the main foil flap.
A= mainfoil retaing bolt hole
B= attachment point of pushrod from mainfoil flap
C= attachment point of of wand spring(holds wand against the water)

One more boat picture:

TomTest schrieb:

Hi Doug,

welcom to our german forum.

Do you mean this link:

http://www.boatdesign.net/forums/mu...lf-righting-trimaran-test-model-36058-55.html

Best Regards

Jens

Zum Vergrößern anklicken....

===================
The link has been changed to: http://www.boatdesign.net/forums/m...lf-righting-trimaran-test-model-36058-59.html This particular post is a summary of all the detail of the boat and is frequently moved to the last page of the thread.

Doug Lord schrieb:

===================
The link has been changed to: http://www.boatdesign.net/forums/m...lf-righting-trimaran-test-model-36058-59.html This particular post is a summary of all the detail of the boat and is frequently moved to the last page of the thread.

Zum Vergrößern anklicken....

Hi Doug,

even though you design for a while from the boatdesign.net or SA forums, I never aksed for more infos... Do you have some videos of this rocket, which btw. looks a bit like a moth with assitance/training wheels
Do you have some experience reports compared to "normal" rc Multis. What about the windrange it requires for foiling. How about the upwind performance. Up to now, the known foilers show foiling just reaching/broad reaching, but neither downwind nor upwind and these are the critical courses on each regatta.

Many thanks

Jens

Für die nicht so englisch affinen:

Ich kenne Dougs design schon seit einer Weile aus anderen Foren, hab aber nie Fragen gestellt und dies hier nun nachgeholt: Video, Erfahrungsbrericht im Vergleich zu normalem RC-Mutlit, und wie schaut es mit Kreuz und Vorm Wind Eigenschaften
aus? Das Konzept hat überigens eher das aussehen einer Motto auf Stützrädern denn mit einem herkömmlichen Mulit.

Grüße

Jens

es war noch nicht im Wasser...

es war noch nicht im Wasser...

it wasn't yet maidened...
so I guess its all still ahrd to tell

EGI1610

Aha... Ich erinnere mich das da schon im September Bilder zu sehen waren...? Da hätte man anehmen können, das es in der Zwischenzeit mal auf dem Wasser war.


Ah, in this case.
I remember I've seen pictures of this device in Septmber/Oktober. So assumed that in the meantime, first results are available.

Best Regards/
Grüße

Jens

Jens, it hasn't sailed yet. But the numbers compare well to the F3 which foiled upwind and took off in realy light air. Nothing will be known for sure until it sails and I will take lots of pictures and video.
See post 882 here: http://www.boatdesign.net/forums/mu...-trimaran-test-model-36058-59.html#post671179

MPX Test Model

MPX Test Model

Here are a couple of pictures of the rig and of the final float test. I've been unable to work on the boat for a long time but am back at it now-shouldn't be long for her first sail. Please visit the thread on boat design if you get a chance: http://www.boatdesign.net/forums/mu...-trimaran-test-model-36058-81.html#post684139

MPS Test Model

MPS Test Model

MPX Test Model--Finally ready to sail!

MPS Test Model

MPS Test Model

Finally ready to sail!Anhang anzeigen 1174130

MPX Test Model----Code Zero

MPX Test Model----Code Zero

MPX Test Model-Code Zero-ready to sail!

Yes Doug! You kept it up! Congratulations. I am so curious to see how she sails. Take your time and report to us as soon as you have something.

Cheers from Sweden! (I am back to real world sailing, so lovely!)

Chris

MPX Test Model

MPX Test Model

Thanks Chris! The big monohull foiler "Mirabaud" has added amas to the boat-not like mine but interesting:

MPX Test Model

MPX Test Model

TomTest schrieb:

Hi Doug,

even though you design for a while from the boatdesign.net or SA forums, I never aksed for more infos... Do you have some videos of this rocket, which btw. looks a bit like a moth with assitance/training wheels
Do you have some experience reports compared to "normal" rc Multis. What about the windrange it requires for foiling. How about the upwind performance. Up to now, the known foilers show foiling just reaching/broad reaching, but neither downwind nor upwind and these are the critical courses on each regatta.

Many thanks

Jens

Für die nicht so englisch affinen:

Ich kenne Dougs design schon seit einer Weile aus anderen Foren, hab aber nie Fragen gestellt und dies hier nun nachgeholt: Video, Erfahrungsbrericht im Vergleich zu normalem RC-Mutlit, und wie schaut es mit Kreuz und Vorm Wind Eigenschaften
aus? Das Konzept hat überigens eher das aussehen einer Motto auf Stützrädern denn mit einem herkömmlichen Mulit.

Grüße

Jens

Zum Vergrößern anklicken....

===========================

"looks a bit like a moth with assitance/training wheels"

Jens, somebody quoted this after a picture of my boat appeared on the front page of SA in their "What is it?" feature. I'm sorry but I hadn't seen it before! The MPX Test Model(Fire Arrow) will work entirely differently than a Moth. The main ,wand controlled, foil is designed to fly the main hull in light air because the fullsize version of this boat has so much righting moment that without the main lifting foil it wouldn't fly the main hull until a wind of 15 knots or more. With the main foil lift it will(should!) fly the main hull in around a 5 knot breeze(fullsize and model). What happens then is the really cool part: as soon as the main hull flys, the boat will speed up and the mainfoil will begin to unload . As it unloads the lee ama foil will begin to take the majority of the weight of the boat with the mainfoil not lifting at all-EXCEPT that, if the wind continues to increase past the wand flight altitude setting, the wand will cause the main foil to create downforce, increasing righting moment similar to the systems on the Osprey and Hobie Trifoiler. When the mainfoil creates downforce it also creates a force to windward,similar to Veal Heel on a Moth.
When the sails and wand are properly set for the conditions, the mainfoil is unloaded EXCEPT(again) that it will act with the rudder foil to control pitch along with the ride angle of the lee UptiP* foil-giving exceptionally good pitch control.
I wanted you to see this before I sail so you (and I) can see if I was right! Will be sailing very shortly.

*This is one of the first trimarans-model or fullsize-to use the UptiP foils invented by Team New Zealand in AC 34. The UptiP foil is used because ,if it is properly designed, it will have automatic altitude control. Only one ama foil is used at a time except before takeoff on the model-on the full size boat the windward ama foil will be retracted. My design of this foil may allow a wider range of operation before the angle of incidence needs to be adjusted-more similar to the GC32 or Flying Phantom. Testing will tell the story......

Hi Doug,

would love to see your MPX flying, can't wait for videos!

Re 'Veal Heel':

Doug Lord schrieb:

... if the wind continues to increase past the wand flight altitude setting, the wand will cause the main foil to create downforce, increasing righting moment similar to the systems on the Osprey and Hobie Trifoiler. When the mainfoil creates downforce it also creates a force to windward, similar to Veal Heel on a Moth.
When the sails and wand are properly set for the conditions, the mainfoil is unloaded EXCEPT(again) that it will act with the rudder foil to control pitch along with the ride angle of the lee UptiP* foil-giving exceptionally good pitch control.

Zum Vergrößern anklicken....

Am I right that I don't see retractable (windward) ama Uptip foils and no movable weight at the MPX, so how would the MPX achieve 'Veal Heel'?
I would like to predict that under 'full load' after a gust the windward foil is slightly immersed (best case). So no need for 'Veal Heel' with a down forced main foil!

So best of luck with the testing!

Cheers,
Wolfgang

MPX Test Model

MPX Test Model

Wolfgang, the Test model will sail with around a 10 degree angle of heel maintained by the dual wands. When that is even slightly exceeded the wand will cause the back end of the flap to go up thereby creating down force. But since the boat is heeled, a component of that downforce will be to windward.

Thanks Doug for the clarification,

I was distracted by the moth's Veal Heel (windward heeling with a foil still producing lift, upwards and windward)

So good luck with your MPX!

Wolfgang