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Jilles Smitts Petrel

Let us all watch your new project progress.
jack
Posts: 73
Joined: 20 Mar 2015, 21:55
Location: chepstow,south wales

Re: Jilles Smitts Petrel

Post by jack »

hi all,thanks to cliff for posting the photos,as you can see the petrel build is now underway,l have chosen the AMT version,simply because it looks pretty!....cliffs cutting is excellent as usual,l am working on the fuz/tail/wing at the same time to speed things up a bit,l fitted hold down blocks to the wing jig as can be seen,the jig is set up for the port wing...it needs to be reversed for the starboard wing,l have chosen to use carbon sheet for the amt crank,together with carbon tubes and rod,purely personal preference,saves a couple of grams in the tail,there are no problems with the build,but there IS a lot of alignment to be checked,cliffs cutting does most of it but it cant do it all, :) :) :) ,something that isnt in the photos is the small support blocks l fitted to the top of the jig..l used these to support the lower main spar in conjunction with tie wraps to secure said spar to the jig to get the correct Gull curve... l suppose tape would work just as well.....l plan on doing monthly updates from here on,these will be mainly pictures,but if l come across anything untoward( ;) ;) ) l will of course explain(l pause here for the sceams of outrage to subside :twisted: :twisted: )so,all well and enjoying the build,back at the end of the month!!

jack
Posts: 73
Joined: 20 Mar 2015, 21:55
Location: chepstow,south wales

Re: Jilles Smitts Petrel

Post by jack »

GUINESS????,Never,real ale only fer this intrepid aviator!!….cheers cliff.

tjarko
Posts: 7
Joined: 08 Dec 2019, 16:56
Location: Netherlands

Re: Jilles Smitts Petrel

Post by tjarko »

Thanks for posting all these pictures. I am looking for my next build project and this could be the one!
As we have no hills in Holland for slope soaring I am looking into something with moderate sink speed. Any guess about weight of this beauty?
Main spar cutouts look quite substantial, how are these made? Size is probably more DIY than model plane shop...

Tjarko

tjarko
Posts: 7
Joined: 08 Dec 2019, 16:56
Location: Netherlands

Re: Jilles Smitts Petrel

Post by tjarko »

Thanks for the info Cliff ..

Bit hard to read, but wing sections are HQ 3,5/18 at the root and HQ 3,5/14 at the tip ?
Still quite thick at the tip, might benefit from a turbulator at 50% chord... Aileron gap will probably do the job too ;-)

Tjarko

Jilles
Posts: 192
Joined: 22 Mar 2015, 10:27
Location: Australia
Contact:

Re: Jilles Smitts Petrel

Post by Jilles »

When the design was created om my computer a 10 kg weight was calculated. the end result is subject to local supplied material density and type of finish and paint used. My Short Nimbus of similar size is 12 kg and fly's very well. it is airborne on the tow within 5 meters.
Without the idea of starting a big discussion, large scale models of this type with a relative large wing area need a bit of weight to make them fly properly.
The 18 and 14% section thickness was determined by data from the original available and is to scale.

Lawrie P
Posts: 35
Joined: 18 May 2017, 21:06
Location: Townsville. North Qld

Re: Jilles Smitts Petrel

Post by Lawrie P »

G,day guys,
Love this glider and might have to build one next year.
I have to agree with the previous comments about the weight. My PWS101 from Jilles plan,which is a similar size and style to the Petrel,weighs in at a bit more than twelve kgs and it flies really nicely and is a bit of a floater. Keep those photos coming of the build.
Cheers everyone.
Compliments of the season to you all.
Happy days
Lawrie.

Lawrie P
Posts: 35
Joined: 18 May 2017, 21:06
Location: Townsville. North Qld

Re: Jilles Smitts Petrel

Post by Lawrie P »

oops. Sorry Cliff. Didnt mean to post that twice. Must have got over excited and double clicked it.
How do i delete one of those posts
Thanks.

jack
Posts: 73
Joined: 20 Mar 2015, 21:55
Location: chepstow,south wales

Re: Jilles Smitts Petrel

Post by jack »

tjarko,get down to your local diy store/builders merchants,have a good sort though their stock of pine and pick out all the close grain stock..avoid the wood with very wide growth rings...choose all clear knot free wood,a visit to ebay should set you up with a good used table saw...fit a blade with a high tooth count (fine/veneer cut),knock up an adjustable jig/fence and away you go,no real need to splash out on top grade spruce ;) ;) ,l now await the screams of outrage at this advice :twisted: :twisted: :twisted: :twisted: ;) ;)

tjarko
Posts: 7
Joined: 08 Dec 2019, 16:56
Location: Netherlands

Re: Jilles Smitts Petrel

Post by tjarko »

Hi Jack,

Good idea to cut the spars from a nice piece of pine.
I have a friend with a table saw.
Inch sizes are hard to get in the Netherlands, better to saw ourselves.
I got pdf preview plans from cliff, very illustrative.

My apologies for creating confusion.
Lets enjoy this beautifull build thread.
I removed my previous remarks as i found them inappropriate in this build log.

Tjarko
Last edited by tjarko on 16 Dec 2019, 09:32, edited 3 times in total.

Jilles
Posts: 192
Joined: 22 Mar 2015, 10:27
Location: Australia
Contact:

Re: Jilles Smitts Petrel

Post by Jilles »

The profile is 18% at the root and 14% at the tip. This is to scale and will fly scale like as well
This is a vintage scale glider with all the behavior of the full scale version and are not a modern glass ship.
All my scale gliders have the same profile and fly as they should. With marginal lift I can outlast in endurance the modern glass jobs but not match their penetration(distance) performance. For local flying this last issue is not a problem.

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