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DJ Aerotech Chrysalis F3-RES to F5-RESt
- Thread starter Konrad
- Start date
Konrad
Very Strong User
Ok, back to something named for something that might metamorphosis into something that might fly.
Here are some dramatic picture of what I needed to do to fit the Aeronaut blade to the CN 25 mm Z hub. This is why I don't recommend this modification. The wall thickness appears to be a bit shy with the 3mm through hole for the pivot pin.
You might notice that I had to notch the black spinner cone to allow the blades to fully open.
I was happy to find that I had a set of Aeronaut 13x8 blades that have the same narrow blade profile as the 12x13. I say this as the 12x13 blade had some weird pull profile in the two climbs I had. It is like the blades are cavitating at low speed and actually get more efficient as the model gains speed. This might not be a problem with such a light model 425 grams. But I do have concerns that the pitch speed is rather high. (You might recall that the original Chrysalis Lite has a flutter problem at speed on the high start).
So once I get the balance and trim issues worked out I may take the climb hit (per the emulation program) and try the 13 x 8 prop.
I test flew with a 44 gram 450mAh 3 cell. I've now ordered some 35 gram 350 mAh 3 cell 55c batteries. I'll wait for them to arrive and check the CG with the new batteries before I start hacking away at things trying to get the desired CG. I might get lucky again and just need to throw money at the problem. My current set of 350 mAh 3 cell rated at 25c just can't cut it at 12 amps!
All the best,
Konrad
Here are some dramatic picture of what I needed to do to fit the Aeronaut blade to the CN 25 mm Z hub. This is why I don't recommend this modification. The wall thickness appears to be a bit shy with the 3mm through hole for the pivot pin.
You might notice that I had to notch the black spinner cone to allow the blades to fully open.
I was happy to find that I had a set of Aeronaut 13x8 blades that have the same narrow blade profile as the 12x13. I say this as the 12x13 blade had some weird pull profile in the two climbs I had. It is like the blades are cavitating at low speed and actually get more efficient as the model gains speed. This might not be a problem with such a light model 425 grams. But I do have concerns that the pitch speed is rather high. (You might recall that the original Chrysalis Lite has a flutter problem at speed on the high start).
So once I get the balance and trim issues worked out I may take the climb hit (per the emulation program) and try the 13 x 8 prop.
I test flew with a 44 gram 450mAh 3 cell. I've now ordered some 35 gram 350 mAh 3 cell 55c batteries. I'll wait for them to arrive and check the CG with the new batteries before I start hacking away at things trying to get the desired CG. I might get lucky again and just need to throw money at the problem. My current set of 350 mAh 3 cell rated at 25c just can't cut it at 12 amps!
All the best,
Konrad
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Konrad
Very Strong User
That's a good question.
I have no brand loyalties. I choose my 350 mAh battery mainly based on physical constraints. I placed my order with Thunder Power as I also needed to get some charger accessories.
I like to give Dinogy a look as they seem to be the best for my EF-1 335 gram batteries.
I avoid Hobby King for ethical reason (FCC issues and others).
If you find a good battery let us know, as I have a lot of UMX models that are in need on new batteries. And with the 250 gram limit these may become a large percentage of my RC fleet.
I have no brand loyalties. I choose my 350 mAh battery mainly based on physical constraints. I placed my order with Thunder Power as I also needed to get some charger accessories.
I like to give Dinogy a look as they seem to be the best for my EF-1 335 gram batteries.
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I avoid Hobby King for ethical reason (FCC issues and others).
If you find a good battery let us know, as I have a lot of UMX models that are in need on new batteries. And with the 250 gram limit these may become a large percentage of my RC fleet.
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I have been debating stocking a lot more of the Dualsky packs. They make some nice high C packs that are tempting. We bring in their cheaper versions for the slow sticks and I have to say I am very pleased with the quality so the higher quality cells are very interesting to me. But probably not anytime soon. We have a lot of work to do around here in the next few months as it is.
Ok i did a little searching. Steven's Aero has Thunder Power packs including the 350 mah ones. Common sense RC has 300 Mah packs with the UMX type blance/charge plug on it. J & H aerospace has 180 2 cell packs for a good price but the balance plug looks bigger than the whole pack. I know Horizon has some packs in stock for their micro planes too. I'll ask around some more about other vendors.
Hank
Hank
Konrad
Very Strong User
I keep forgetting about Steven's Aero and my "smaller" electrical needs.
I see that the TP-350 are $2 cheeper. Now as a customer what always concerns me when dealing with the purchase of Liops is how old is the new stock? It is my experience that lipos that are 2 years old have lost a noticeable amount of their performance*. This is why Lipos are one of the few items I don't purchase on sale. It is also why I generally don't look for Lipo batteries from stores that don't specialize in batteries.
I need to say that all the batteries regardless of their chemistry that I've purchased from Aloft have performed great. I've bought single cell 300 mAh through 8 cell 5500 mAh lipos and a host of NiMh TX/RX batteries.
*When I notice that a cell has lost about 80% of their performance I think of it as dead.
All the best,
Konrad
I see that the TP-350 are $2 cheeper. Now as a customer what always concerns me when dealing with the purchase of Liops is how old is the new stock? It is my experience that lipos that are 2 years old have lost a noticeable amount of their performance*. This is why Lipos are one of the few items I don't purchase on sale. It is also why I generally don't look for Lipo batteries from stores that don't specialize in batteries.
I need to say that all the batteries regardless of their chemistry that I've purchased from Aloft have performed great. I've bought single cell 300 mAh through 8 cell 5500 mAh lipos and a host of NiMh TX/RX batteries.
*When I notice that a cell has lost about 80% of their performance I think of it as dead.
All the best,
Konrad
I ordered some 180 2 cells from J & H I also ordered a 2 cell 300 mah HV pack from them too. I've never used a Hv pack so it'll be an interesting experiment. I think i have a good plane to put the battery in. I'll let you know what I think of the batteries when i get them.
Good notes on batteries and conditions. I too have really liked all the batteries i have bought from Aloft. Makes me wish they stocked more.
Hank
Good notes on batteries and conditions. I too have really liked all the batteries i have bought from Aloft. Makes me wish they stocked more.
Hank
Thanks guys - Like you all, I use our products! I don't want dead batteries either, so I buy in small quantities that I know I can sell in a short period of time. For NiMH this simply means we can no longer stock all of the pack sizes we used to as demand for them has been dropping. For lipo, it is a tough act as their are SO MANY different sizes and needs for people. What is hot today will not sell tomorrow. It is a balancing act. Our suppliers also fight this hot and cold demand issue. I constantly see them over stocked on some odd size, yet a popular size may not have inventory for many months.
Following a trade show, I shared a rental car with another RC company and we chatted during the drive to the airport. Aloft did not sell lipos yet. I asked about safety concerns and shipping, etc. I was told that the only way to make money with Lipos was to buy them by the container load and hope they all sell. That company is no longer in business. Among other things they had a rep for under performing batteries.
I'd love to buy 100s of each pack size, but typically we are buying 10 or 20 of a given SKU, sometimes just 2 depending on the sales history. This guarantees that our cells are always fresh. For Nihms we have to buy 100 of each pack at a time, and that is getting harder and harder to do as the sales for this style battery drops, and they have the shortest shelf life of any battery chemistry.
The other side of the equation is to buy new stock from the manufacturer. You don't want cells that have been sitting in their warehouse either. We are very selective of our suppliers for this reason. To me this is an important part of our business and I treat it as such.
Following a trade show, I shared a rental car with another RC company and we chatted during the drive to the airport. Aloft did not sell lipos yet. I asked about safety concerns and shipping, etc. I was told that the only way to make money with Lipos was to buy them by the container load and hope they all sell. That company is no longer in business. Among other things they had a rep for under performing batteries.
I'd love to buy 100s of each pack size, but typically we are buying 10 or 20 of a given SKU, sometimes just 2 depending on the sales history. This guarantees that our cells are always fresh. For Nihms we have to buy 100 of each pack at a time, and that is getting harder and harder to do as the sales for this style battery drops, and they have the shortest shelf life of any battery chemistry.
The other side of the equation is to buy new stock from the manufacturer. You don't want cells that have been sitting in their warehouse either. We are very selective of our suppliers for this reason. To me this is an important part of our business and I treat it as such.
Konrad
Very Strong User
Interesting, small HV cells. Please let us know how they work out for you.
HV Lipos have not worked well for me. I got only around 25 charge discharge cycles before they puffed. I was using then in the high current application of EDF. I was hoping to use the HV to make up for the performance loss flying at 6K to 7K feet. It worked but the life of the cell was drastically cut down when charged to 4.35V. Even trying to stay near half the "C" discharge rating the cell failed. Changing the impeller to a 9 bladed impeller worked much better (higher load). (Most EDF are now going to the 9 blade for the 80mm to 90mm EDF).
Please be aware that many 6cell ESC are using MOFETs that actually are only rated for 20v. They may get away with this when the cell peak voltage is 4.20V but going to 4.35V may damage these 20v rated MOSFETs.
Back to the Chrysalis Lite F5-RESt the TP-350 mAh cell did not move the CG aft enough. I'll have to recover the V tail with a heavier more durable covering film.
HV Lipos have not worked well for me. I got only around 25 charge discharge cycles before they puffed. I was using then in the high current application of EDF. I was hoping to use the HV to make up for the performance loss flying at 6K to 7K feet. It worked but the life of the cell was drastically cut down when charged to 4.35V. Even trying to stay near half the "C" discharge rating the cell failed. Changing the impeller to a 9 bladed impeller worked much better (higher load). (Most EDF are now going to the 9 blade for the 80mm to 90mm EDF).
Please be aware that many 6cell ESC are using MOFETs that actually are only rated for 20v. They may get away with this when the cell peak voltage is 4.20V but going to 4.35V may damage these 20v rated MOSFETs.
Back to the Chrysalis Lite F5-RESt the TP-350 mAh cell did not move the CG aft enough. I'll have to recover the V tail with a heavier more durable covering film.
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Konrad
Very Strong User
OK, with the 3 cell 350mAh, 34 gram Thunder Power Rampage battery and with the nose at 205mm from the LE to the spinner back plate my CG is at 87mm to 85mm. This is with an AUW of 422 grams.
A CG of 87mm is what the plans show. I recall that I liked the CG at about 90mm when I flew her as an F3-RES ship.
As is typical with me the conversion got a bit more involved. Not only did I have to cut off the lead ladened nose and make a pressure cowl and motor mount. But I had to change over to the diagonally braced balsa tail. This was actually too effective at removing weight from the tail. So I had to resort to covering the V-tail with full weight transparent Oracover. I did leave the flippers covered with white So-Lite covering.
With a close examination of the battery leads to remove maybe 40mm of wire and adding an other layer or two of skid tape to the bottom of the V-tail I think I can hit my old CG or 90mm.
Now I have to ask what are you all using, if anything, to keep the blades folded back along the fuselage? Historically with the weight of the models I fly the slipstream was enough to keep the blades aft in glide. But these F5-RESt ship really are light and can fly with a surprisingly low air speed.
I just finished recovering the V-tail and have yet to go out for a second set of flight tests.
All the best,
Konrad
A CG of 87mm is what the plans show. I recall that I liked the CG at about 90mm when I flew her as an F3-RES ship.
As is typical with me the conversion got a bit more involved. Not only did I have to cut off the lead ladened nose and make a pressure cowl and motor mount. But I had to change over to the diagonally braced balsa tail. This was actually too effective at removing weight from the tail. So I had to resort to covering the V-tail with full weight transparent Oracover. I did leave the flippers covered with white So-Lite covering.
With a close examination of the battery leads to remove maybe 40mm of wire and adding an other layer or two of skid tape to the bottom of the V-tail I think I can hit my old CG or 90mm.
Now I have to ask what are you all using, if anything, to keep the blades folded back along the fuselage? Historically with the weight of the models I fly the slipstream was enough to keep the blades aft in glide. But these F5-RESt ship really are light and can fly with a surprisingly low air speed.
I just finished recovering the V-tail and have yet to go out for a second set of flight tests.
All the best,
Konrad
u2builder
Strong User
I just happened upon this thread while trying to find out why the Chrysalis 2m pod and boom was discontinued. the D&J website seems to indicate that booms were not available but that seems odd.
I like building and am curious about a good choice for a 2m electric glider. Konrad, I'd be interested in your comparison of the Chrysalis you built (that isn't available, the Monarch Ascension, and the Yellow Jacket, which uses the carbon fiber tube spar instead of the more conventional spar. I will never be competing but am still interested in how these designs compare.
BTW I used one of those little 25mm spinners when I electrified a l plans built 1m Mimi DLG with a direct drive drone motor and couldn't find a prop that would fold. When I finally found one that had a 5mm hub and 2mm pin hole it wouldn't fold. I cut as big a notch as I dared in the tiny spinner and then sanded away the hub much as you did. It would be nice to have props that match these nice hubs.
I like building and am curious about a good choice for a 2m electric glider. Konrad, I'd be interested in your comparison of the Chrysalis you built (that isn't available, the Monarch Ascension, and the Yellow Jacket, which uses the carbon fiber tube spar instead of the more conventional spar. I will never be competing but am still interested in how these designs compare.
BTW I used one of those little 25mm spinners when I electrified a l plans built 1m Mimi DLG with a direct drive drone motor and couldn't find a prop that would fold. When I finally found one that had a 5mm hub and 2mm pin hole it wouldn't fold. I cut as big a notch as I dared in the tiny spinner and then sanded away the hub much as you did. It would be nice to have props that match these nice hubs.
Konrad
Very Strong User
On the spinner question I have a light review of the CN 25mm "Z" hub spinner. They CN have 2 sets of blades that fit real well on the "Z" hub and against narrow nosed F3K type fuselages. These are 7x4 and 6x4 and are matched rather well with the Quad motors that they are intended to be attach.
forum.alofthobbies.com
OK, the Chrysalis 2m is an entry level glider with a focus on being easy to build, strong and easy to repair. It was never intended to be a competition class sailplane. I've never seen it sold with a boom and pod fuselage. This would be contrary to the idea of being easy to build, strong and easy to repair.
The Chrysalis-Lite F3-RES is a competition ship. It was DJAerotech's first entry into the class. It was based on the smaller 1.5m boom and pod hand launch glider. As this wasn't a clean sheet design there are some Issue. First to reach the 2 meter span they needed to add a 0.5m center section. To handle the bending loads the airfoil in this section had to be made thicker. Blending this thick center section into the thinner outer panels resulted in some of the carbon spar caps needing to be preloaded while building the outer panels. (Not really a problem just a bit more work on the building board).
And then there was the carbon tail boom. This proved to be the Achilles heal of the design! It allowed (encouraged) flutter! It wasn't until late in the production life that the true cause was found. That is because of the very small diameter of the tapered tail boom. DJArotech used far too small a set of control horns for the V-Tail flippers. This became a geometry issue with the control system. Don Stackhouse knew this but thought that as this was a competition ship that the builders would know how to hinge and set up control linkages to make this not an issue on the weak F3-RES high starts (8lb pull). This proved to be a bad assumption! At the time on introduction Don knew the tail boom was too small and was expecting a new tapered boom to come onto the kite market, it never happened. As the flutter reports came in Don came up with the upgraded diagonally braced balsa V-Tail. (I added the diagonal braces when I first saw the tail of the original bass wood tail). This did not address the linkage issues. So a second upgrade was made known as the "U" tail. ( I choose to go with the diagonally braced balsa tail for weight savings and that I didn't think I will reach the speed we reach on a high start with the motorized F5 RESt).
I like the fully fleshed out fuselages as they are often stronger, lighter and easier to build. The only advantage I see in the carbon tail boom is speed of construction and then it is just the amount of time saved sanding the balsa fuse to shape. Then there are the problems with repair.
The Chrysalis-Lite F3-RES fuselage has too short a nose resulting in the need for far too much nose weight. This killed the performance on the weak high start as one needed to add 30g to 50g to get the balance even to 90mm. While the The Chrysalis-Lite F3-RES build nice and light it trims out rather heavy for its class at 425 to 435 grams with Oracover lite. The Yellow Jacket is much better here in that most are coming in under 400grams. (This 35 grams (9% penalty) really shows up on the high start. In the glide I find the added weight more often than not actually helps when covering ground looking for lift)
Of the 3 F3-RES ships you mention. The Chrysalis-Lite F3-RES is an also ran not only because of production problems obtaining the proper tapered carbon boom but also because of the short nose.
I don't like the Yellow Jacket's use of round pultruded carbon tubes as spars. This is because the tube is a horrible waste of carbon when it come to resisting the bending and torsional loads of a wing. I also don't like the LE covering sag. (Note DJAerotech on the Chrysalis family, does use a rib profile that minimized this getting the LE shape close to that of a sheeted LE. It recovers all but about 15% of the drag lost to typical LE sag)
I really like the engineering that went into the Ascension. The downside is that it is a much more advanced build with its sheeted LE than the Chrysalis with its diagonally braced open LE. While on paper the Ascension looks to have better performance numbers across the whole flight envelope (against the Chrysalis-lite). The fact that it has about 100 square inches less area means that for most pilots the Chrysalis-Lite will actually fly better. (Is more forgiving near and after the stall).
I go into more design detail with the Chrysalis-lite here.
More thought on spoilers
forum.alofthobbies.com
All the best,
Konrad
P.S.
I see the question is about an electric 2 meter kits. I don't recommend what I've done with my Chrysalis Lite. It is far too expensive for the geared motor. Then there is the real risk with the prop pivots. I think the Chrysalis 2 meter electric is a great entry level electric glider in the same vein as the old Astro Flight Challenger! I don't like the Ascension electric as sold by DJArotech as it looks gross with that large motor and spinner. I'd also like to see more wing on the Ascension as an electric.
CN Models 25mm Z hub Collet spinner
I'm finding that the CN Models 25mm spinner with Z hub is turning out to be very practical in many of my smaller light F5-RES and F5K models. I did find a minor problem with the CN Models 7x4 blade and the spinner. That is the spinner keeps the blades from fully opening up. This caused a massive...
forum.alofthobbies.com
OK, the Chrysalis 2m is an entry level glider with a focus on being easy to build, strong and easy to repair. It was never intended to be a competition class sailplane. I've never seen it sold with a boom and pod fuselage. This would be contrary to the idea of being easy to build, strong and easy to repair.
The Chrysalis-Lite F3-RES is a competition ship. It was DJAerotech's first entry into the class. It was based on the smaller 1.5m boom and pod hand launch glider. As this wasn't a clean sheet design there are some Issue. First to reach the 2 meter span they needed to add a 0.5m center section. To handle the bending loads the airfoil in this section had to be made thicker. Blending this thick center section into the thinner outer panels resulted in some of the carbon spar caps needing to be preloaded while building the outer panels. (Not really a problem just a bit more work on the building board).
And then there was the carbon tail boom. This proved to be the Achilles heal of the design! It allowed (encouraged) flutter! It wasn't until late in the production life that the true cause was found. That is because of the very small diameter of the tapered tail boom. DJArotech used far too small a set of control horns for the V-Tail flippers. This became a geometry issue with the control system. Don Stackhouse knew this but thought that as this was a competition ship that the builders would know how to hinge and set up control linkages to make this not an issue on the weak F3-RES high starts (8lb pull). This proved to be a bad assumption! At the time on introduction Don knew the tail boom was too small and was expecting a new tapered boom to come onto the kite market, it never happened. As the flutter reports came in Don came up with the upgraded diagonally braced balsa V-Tail. (I added the diagonal braces when I first saw the tail of the original bass wood tail). This did not address the linkage issues. So a second upgrade was made known as the "U" tail. ( I choose to go with the diagonally braced balsa tail for weight savings and that I didn't think I will reach the speed we reach on a high start with the motorized F5 RESt).
I like the fully fleshed out fuselages as they are often stronger, lighter and easier to build. The only advantage I see in the carbon tail boom is speed of construction and then it is just the amount of time saved sanding the balsa fuse to shape. Then there are the problems with repair.
The Chrysalis-Lite F3-RES fuselage has too short a nose resulting in the need for far too much nose weight. This killed the performance on the weak high start as one needed to add 30g to 50g to get the balance even to 90mm. While the The Chrysalis-Lite F3-RES build nice and light it trims out rather heavy for its class at 425 to 435 grams with Oracover lite. The Yellow Jacket is much better here in that most are coming in under 400grams. (This 35 grams (9% penalty) really shows up on the high start. In the glide I find the added weight more often than not actually helps when covering ground looking for lift)
Of the 3 F3-RES ships you mention. The Chrysalis-Lite F3-RES is an also ran not only because of production problems obtaining the proper tapered carbon boom but also because of the short nose.
I don't like the Yellow Jacket's use of round pultruded carbon tubes as spars. This is because the tube is a horrible waste of carbon when it come to resisting the bending and torsional loads of a wing. I also don't like the LE covering sag. (Note DJAerotech on the Chrysalis family, does use a rib profile that minimized this getting the LE shape close to that of a sheeted LE. It recovers all but about 15% of the drag lost to typical LE sag)
I really like the engineering that went into the Ascension. The downside is that it is a much more advanced build with its sheeted LE than the Chrysalis with its diagonally braced open LE. While on paper the Ascension looks to have better performance numbers across the whole flight envelope (against the Chrysalis-lite). The fact that it has about 100 square inches less area means that for most pilots the Chrysalis-Lite will actually fly better. (Is more forgiving near and after the stall).
I go into more design detail with the Chrysalis-lite here.
More thought on spoilers
Spoiler Drag link
I hate spoiler! With that out of the way here is how I like to actuate spoilers. This set up is known as a drag link. It maintains a possitive connection with the spoiler and servo. Does not need or use any springs or magnets. Adjustments are easily controled by the radio's end point and /or...
forum.alofthobbies.com
All the best,
Konrad
P.S.
I see the question is about an electric 2 meter kits. I don't recommend what I've done with my Chrysalis Lite. It is far too expensive for the geared motor. Then there is the real risk with the prop pivots. I think the Chrysalis 2 meter electric is a great entry level electric glider in the same vein as the old Astro Flight Challenger! I don't like the Ascension electric as sold by DJArotech as it looks gross with that large motor and spinner. I'd also like to see more wing on the Ascension as an electric.
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Glenn Beer
Active User
I never did post a pic of the finished Element 2 Pure Glider conversion to electric looks like.
Konrad
Very Strong User
I have to admit that I've just been using the that looks about right method for the grafting on of the motor. I just measure my down thrust at 5.5+ degrees using the flat part of the wing saddle as my datum. I normally use the stab as my datum. Even then that would still leave me with about 4° of down thrust. I'll have to keep an eye on this as I go through my flight tests.
P.S.
From the stab I have 4.6 to 4.7° down thrust
P.S.
From the stab I have 4.6 to 4.7° down thrust
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Glenn Beer
Active User
Went back and checked the Element’s down thrust again.
vs the elevator as a zero. I get 6 deg +/- 0.1
vs the saddle flat. 5 deg +/- 0.1
An incidence of 1deg. Sounds about right.
Redo fatigue prevents me from adding more. That and the fear that 2 more degrees might be just too much.
vs the elevator as a zero. I get 6 deg +/- 0.1
vs the saddle flat. 5 deg +/- 0.1
An incidence of 1deg. Sounds about right.
Redo fatigue prevents me from adding more. That and the fear that 2 more degrees might be just too much.
