(Something Fast?) Delta Build Thread
#1
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
(Something Fast?) Delta Build Thread
Between my addiction to Deltas and my addiction to speed I kept thinking of what would make the perfect Delta. It seems that the Delta’s I am aware of all seem to have shortcomings so I made a list of what I would change. While a Delta may never win the German Speedcup, I have not seen any real attempts to be competitive. I may not be qualified to design a world champion speed plane but basic issues can easily be addressed.
This Delta is my design and my goal is to have a very clean airframe that will fly really fast or really slow. Most Delta models either have everything out in the breeze, weight too much or both. Deltas look good by default so making it look even better should not be hard. These were my goals during the design phase.
1. Reduce all drag. Drag is enemy #1 to speed so a clean design is important. (easy full engine cowl)
2. Low weight. Heavy airplanes do not fly well and it increases drag.
3. Build in a couple of days, not weeks or months.
4. Cost $100 or less to build.
5. Look good.
Specifications:
Wingspan – 32 in
Wing area – 475 sq. in.
Weight – three pounds with a 40-50 glow engine
This Delta is my design and my goal is to have a very clean airframe that will fly really fast or really slow. Most Delta models either have everything out in the breeze, weight too much or both. Deltas look good by default so making it look even better should not be hard. These were my goals during the design phase.
1. Reduce all drag. Drag is enemy #1 to speed so a clean design is important. (easy full engine cowl)
2. Low weight. Heavy airplanes do not fly well and it increases drag.
3. Build in a couple of days, not weeks or months.
4. Cost $100 or less to build.
5. Look good.
Specifications:
Wingspan – 32 in
Wing area – 475 sq. in.
Weight – three pounds with a 40-50 glow engine
#2
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
I have built a few kits but scratch building is not my forte. I modified a copy of my plans and sent them to Top Notch Products for laser cutting. I was amazed on how well the parts fit together. I guess they should but I kept thinking I was over looking a big mistake but that was not the case. I gathered up the wood and parts listed on my material list and set everything out to start building. I liked the carbon fiber spars on the Dust so well I put out the couple of extra $ to go that route.
#3
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
With a wing span of just 2" more then a clipped wing Dust the building area does not need to be very big. We will see if i can build it on a 30" x 40" dinette table.
For phase 1 of the building I gathered up the spars, ribs, engine mount, firewall, 1/4" dowel and two screws. The airfoil is a NACA 0006 but with the #1 ribs being over 22" long the maximum thickness is a little over an inch. The engine mount is just over 3" long so the engine can be set back far enough for a spinner to be close to the nose ring. I guess a rear intake fan engine would fit with a little effort.
I kept trying to think of a good way to attach the spars to the last rib and came up with a way I think will work well. I put a 1/4" dowel in the end of each spar with the long spar dowel cut off flush and the front spar dowel sticking out 3/16". The #4 rib height would not allow drilling a 1/4" hole and still be strong.
To make sure the airframe was straight I used two 1/2" hardwood rails with 3/16" supports as seen in the picture below. I just push down on the spars and everything aligned perfect. Thin CA glue on every joint except the last rib with a screw in it.
For phase 1 of the building I gathered up the spars, ribs, engine mount, firewall, 1/4" dowel and two screws. The airfoil is a NACA 0006 but with the #1 ribs being over 22" long the maximum thickness is a little over an inch. The engine mount is just over 3" long so the engine can be set back far enough for a spinner to be close to the nose ring. I guess a rear intake fan engine would fit with a little effort.
I kept trying to think of a good way to attach the spars to the last rib and came up with a way I think will work well. I put a 1/4" dowel in the end of each spar with the long spar dowel cut off flush and the front spar dowel sticking out 3/16". The #4 rib height would not allow drilling a 1/4" hole and still be strong.
To make sure the airframe was straight I used two 1/2" hardwood rails with 3/16" supports as seen in the picture below. I just push down on the spars and everything aligned perfect. Thin CA glue on every joint except the last rib with a screw in it.
#4
Senior Member
My Feedback: (14)
Join Date: May 2005
Location: GRIFTON,
NC
Posts: 488
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
I like it!
Simple, efficient, cheap and fast that's exactly how it should be![sm=thumbup.gif]
I have never owned a or flew a delta but it looks fun!
I'll be watchin'
SJ
Simple, efficient, cheap and fast that's exactly how it should be![sm=thumbup.gif]
I have never owned a or flew a delta but it looks fun!
I'll be watchin'
SJ
#5
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
ORIGINAL: SPEED JUNKIE
I like it!
Simple, efficient, cheap and fast that's exactly how it should be![sm=thumbup.gif]
I have never owned a or flew a delta but it looks fun!
I'll be watchin'
SJ
I like it!
Simple, efficient, cheap and fast that's exactly how it should be![sm=thumbup.gif]
I have never owned a or flew a delta but it looks fun!
I'll be watchin'
SJ
There is a reason for several in this forum to have more then one Delta. It may be time to try one.
#6
Join Date: Dec 2003
Location: Colliers WoodLondon, UNITED KINGDOM
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Mike
I like you build, looks good similar to my own delta.
Keep us posted.
Andre
--------------------------------------------------------------------------------
http://www.vimeo.com/clip:209833
http://www.vimeo.com/clip:209359
I like you build, looks good similar to my own delta.
Keep us posted.
Andre
--------------------------------------------------------------------------------
http://www.vimeo.com/clip:209833
http://www.vimeo.com/clip:209359
#8
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
ORIGINAL: Razor-RCU
Mike- NICE WORK!
I will definitely buy one of these-
Mike- NICE WORK!
I will definitely buy one of these-
Did I say I was going to sell them?
At this point it would be easy to put together a few kits but that may be a little premature. First it needs to fly well, fast and hold together in a 20G turn.
#9
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Next comes the leading edge, trailing edge and wing tips.
I did not want a blunt leading edge and first thought about using 1/4" bass wood. However, with the 48* wing sweep the hard wood did not have much mating surface on the ribs. After some testing I decided on mid weight balsa as it let me use firm pressure for the surfaces to fit well and the sheeting made it surprisingly strong. While it will take mild abuse I would not fly it into a tree and expect no damage.
Tilting the end ribs up I was able to see a perfect alignment before installing the trailing edge and then gluing everything including the end rib screw joint. I also install 1/4" tri stock on the trailing edge for the elevon to pivot on.
Wing tips are out of 3/8" x 2" balsa and cut as shown on plans after putting a 20* bevel on one edge with a small table saw. I marked the center on the edges and started sanding. An electric sander would have been nice.
The second picture shows the laser cut vertical fin support with spacers on the fin support and bottom sheeting for a 10* fin tilt. I hope the patch repair does not through off the lateral balance.
The sharp leading edge and the the wing tip design was discussed in the aerodynamics section and it seems I am not breaking any rules to create unwanted vortices's. Those guys are not afraid to point out problem areas if you have a bad idea I found out.
I did not want a blunt leading edge and first thought about using 1/4" bass wood. However, with the 48* wing sweep the hard wood did not have much mating surface on the ribs. After some testing I decided on mid weight balsa as it let me use firm pressure for the surfaces to fit well and the sheeting made it surprisingly strong. While it will take mild abuse I would not fly it into a tree and expect no damage.
Tilting the end ribs up I was able to see a perfect alignment before installing the trailing edge and then gluing everything including the end rib screw joint. I also install 1/4" tri stock on the trailing edge for the elevon to pivot on.
Wing tips are out of 3/8" x 2" balsa and cut as shown on plans after putting a 20* bevel on one edge with a small table saw. I marked the center on the edges and started sanding. An electric sander would have been nice.
The second picture shows the laser cut vertical fin support with spacers on the fin support and bottom sheeting for a 10* fin tilt. I hope the patch repair does not through off the lateral balance.
The sharp leading edge and the the wing tip design was discussed in the aerodynamics section and it seems I am not breaking any rules to create unwanted vortices's. Those guys are not afraid to point out problem areas if you have a bad idea I found out.
#10
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Before starting the component compartment and hatch I sheeted much of the bottom including the 1”strips on the leading and trailing edge. The hatch area has no predefined height but will be determined by the fuel tank and servos. There was plenty of room for an 8 oz. Tank but I am going with a 6-oz slant tank. Servo rails have been installed so a minimum compartment height could be determined.
At that point I took two sheets of 3/32” balsa and glued the ends together so I could work on them as a unit. I rested them on the spar on the outside of the #1 rib so I could mark the rib contour, servo rails and bulkheads. I also marked the height needed to clear the components inside. The balsa ahead of the firewall was left intact so it could be later pulled into the nose ring and glued. Any cutting in this area was kept square with building a full engine cowl in mind. The engine will be partially cowled just by design.
After forming the balsa I separated the two sheets. I then glued the two matched pieces to the inside of each #1 rib. I then glued tri stock so the hatch would have a resting place and room to round by sanding.
I really hate to add weight to balance a plane so I left access to the area behind the spar for the battery if tail weight is needed.
At that point I took two sheets of 3/32” balsa and glued the ends together so I could work on them as a unit. I rested them on the spar on the outside of the #1 rib so I could mark the rib contour, servo rails and bulkheads. I also marked the height needed to clear the components inside. The balsa ahead of the firewall was left intact so it could be later pulled into the nose ring and glued. Any cutting in this area was kept square with building a full engine cowl in mind. The engine will be partially cowled just by design.
After forming the balsa I separated the two sheets. I then glued the two matched pieces to the inside of each #1 rib. I then glued tri stock so the hatch would have a resting place and room to round by sanding.
I really hate to add weight to balance a plane so I left access to the area behind the spar for the battery if tail weight is needed.
#11
Senior Member
My Feedback: (50)
Join Date: Mar 2002
Location: Mira Mesa, CA
Posts: 5,405
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
I dunno Mike, I have been reading your posts for years and you are a Whiz. If you are designing a delta, even for fun, it is going to rock- IF it becomes a kit I want one If not then I want video!
You are a true speed-freak and you even apply like Aerodynamics and stuff to your posts, I can fly alright but I am basically a 4th grader com pared to you, Bob27, Flyboy dave and others when it comes to design/build/explain what we do.
Cheer to you my friend!
james
You are a true speed-freak and you even apply like Aerodynamics and stuff to your posts, I can fly alright but I am basically a 4th grader com pared to you, Bob27, Flyboy dave and others when it comes to design/build/explain what we do.
Cheer to you my friend!
james
#12
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
James,
I am flattered but there are a few pretty sharp guys in this forum. We all have our area and I just try to learn from others and make contributions when I can.
As far as my my design, time will tell. I am not reinventing the wheel here but taking proven concepts and putting all the good parts together.
I am flattered but there are a few pretty sharp guys in this forum. We all have our area and I just try to learn from others and make contributions when I can.
As far as my my design, time will tell. I am not reinventing the wheel here but taking proven concepts and putting all the good parts together.
#13
Join Date: Dec 2003
Location: Colliers WoodLondon, UNITED KINGDOM
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Mike Looking good.
I have used 6 mm carbon rods in my delta's leading edge, and cut a half circle in the LE of the ribs to accept the carbon rod.
Also, I found a good 2" capstrip allong the leading edge helps when covering the wing.
But looking good.
My next version will have a smaller span and maybe a 3 mm carbon rod in the leading edge.
Andre
I have used 6 mm carbon rods in my delta's leading edge, and cut a half circle in the LE of the ribs to accept the carbon rod.
Also, I found a good 2" capstrip allong the leading edge helps when covering the wing.
But looking good.
My next version will have a smaller span and maybe a 3 mm carbon rod in the leading edge.
Andre
#14
Senior Member
RE: (Something Fast?) Delta Build Thread
Mike, it looks like your are building a mini BTE Vortex. Where will the retracts go? Smile! Thanks for sharing the pics of your Vortex and attached a couple of pics of mine under construction, Ron H
#15
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
ORIGINAL: acr007
Mike Looking good.
I have used 6 mm carbon rods in my delta's leading edge, and cut a half circle in the LE of the ribs to accept the carbon rod.
Also, I found a good 2" capstrip allong the leading edge helps when covering the wing.
But looking good.
My next version will have a smaller span and maybe a 3 mm carbon rod in the leading edge.
Andre
Mike Looking good.
I have used 6 mm carbon rods in my delta's leading edge, and cut a half circle in the LE of the ribs to accept the carbon rod.
Also, I found a good 2" capstrip allong the leading edge helps when covering the wing.
But looking good.
My next version will have a smaller span and maybe a 3 mm carbon rod in the leading edge.
Andre
I have had two Diamond Dust with 7mm glass rods for leading edges and considered a smaller rod on my design. The good side to the rod is they are very durable. My reasons for not using a CF rod is weight, cost and I would have to add tri stock to get the desired sharper leading edge. The 3mm would not be too blunt though. Many model airplanes use balsa leading edges with sheeting and it is very light and surprisingly durable.
What is the span of your delta?
#16
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Hi airbusdrvr,
If we put them side by side I suspect "mini" would be a good word to describe mine. The distance from the bottom of the rib to the spar was less then 1/2" so I deceided not to install retracts on this one.
#17
Join Date: Dec 2003
Location: Colliers WoodLondon, UNITED KINGDOM
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
Hey Mike
Yep I agree with what you say, it does keep the cost down.
My delta is a 37.25 inch span and 21 inch chord.
Andre
Yep I agree with what you say, it does keep the cost down.
My delta is a 37.25 inch span and 21 inch chord.
Andre
#19
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
ORIGINAL: Troy-RCU
That looks cool. Are you going to post PDF plans for this when done?
That looks cool. Are you going to post PDF plans for this when done?
My hats off to the scratch builders. I adjust my drawing .003" for laser kerf for the perfect fit and some guy makes it fit with a saw? My eyes work in tenths of an inch, not thousandths.
If it flies well the work is already done for throwing together a short kit with printed plans for not much money. I don't want to get ahead of myself though.
#20
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
If this thing flies as fast as it builds then watch out. Since this is a prototype I am not going to put a $350 Jett 60 LX on it but will test the airframe with a TT 46 Pro.(I know I know) I am also experimenting with engine cowls and would hate to overheat an expensive engine. I have enough parts to build two airplanes and the second will be a different animal.
It was tempting to add more sheeting then my plans called for but I resisted. The open bays are not that big and bottom damage during landings should be less then my Dust. After applying the top center sheeting I put tri stock along the fuse area for a poor mans fillet. The nose ring was installed and the fuse sides that extended to the front were trimmed and pulled into the nose ring and glued. I also streamlined the bottom of the engine compartment.
The vertical fins were sanded but not glued in and the elevons were hinged. I think I will cover the plane before gluing the fins in because of the tight space between them and the hatch. The elevons will be installed before covering so I won’t have to reseal them.
I am going to reinforce several areas with fiberglass cloth and cut out what I would need. The large piece in the middle is actually going on the belly to protect it during landings.
The three most difficult things so far have been sanding the wing tips (razor plain on order), determining the sequence of assembly and not twisting the airframe while sheeting. Frequent checks for a straight airframe show it straight and the sheeting will now keep it that way.
It was tempting to add more sheeting then my plans called for but I resisted. The open bays are not that big and bottom damage during landings should be less then my Dust. After applying the top center sheeting I put tri stock along the fuse area for a poor mans fillet. The nose ring was installed and the fuse sides that extended to the front were trimmed and pulled into the nose ring and glued. I also streamlined the bottom of the engine compartment.
The vertical fins were sanded but not glued in and the elevons were hinged. I think I will cover the plane before gluing the fins in because of the tight space between them and the hatch. The elevons will be installed before covering so I won’t have to reseal them.
I am going to reinforce several areas with fiberglass cloth and cut out what I would need. The large piece in the middle is actually going on the belly to protect it during landings.
The three most difficult things so far have been sanding the wing tips (razor plain on order), determining the sequence of assembly and not twisting the airframe while sheeting. Frequent checks for a straight airframe show it straight and the sheeting will now keep it that way.
#21
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
You can see where the fiberglass was put down. pay no attention to the cowl in one of the pics. My second cowl attempt has wet paint on it and not shown. I used fiberglass and sheeting rather then kevlar thread to secure the leading edge. It seems like I use the wing tips for handles so I reinforced them and of course the belly for landing. It is ready to cover and the weight is 12.2 oz.
#22
Senior Member
My Feedback: (1)
Join Date: Jan 2002
Location: Oceanside,
CA
Posts: 525
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
What about a thin piece of ply on the bottom to act as a skid and double as a grip to hand launch? Wouldn't add any significant drag but would save the covering and sheeting on rough runways. Still looking for a home for my 6.5 and this might be the ticket!
#23
Senior Member
Thread Starter
My Feedback: (5)
Join Date: Jan 2002
Location: Tulsa, OK
Posts: 2,025
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
ORIGINAL: Troy-RCU
What about a thin piece of ply on the bottom to act as a skid and double as a grip to hand launch? Wouldn't add any significant drag but would save the covering and sheeting on rough runways. Still looking for a home for my 6.5 and this might be the ticket!
What about a thin piece of ply on the bottom to act as a skid and double as a grip to hand launch? Wouldn't add any significant drag but would save the covering and sheeting on rough runways. Still looking for a home for my 6.5 and this might be the ticket!
Aren't you an electric guy? The plans show a back plate mount for an electric motor. The servos could be mounted behind the rear spar and there would be tons of room for a $500 battery behind a Neu 1509. If not a 6.5 would work.
#24
Senior Member
Join Date: Jan 2005
Location: Sydney, AUSTRALIA
Posts: 852
Likes: 0
Received 0 Likes
on
0 Posts
RE: (Something Fast?) Delta Build Thread
lookin good Mike and very similar to my current project also..a fully sheeted/glassed DD..I used green florist foam to make the cowl moldings..(three piece)..shapes very easily but the sanding dust is a bugger to get rid of
good luck with it and I'll keeping checking in on the progress.
good luck with it and I'll keeping checking in on the progress.