Ah! What a great day!
First dispelling a bit of confusion:
Rustom 1 is a modified LongEZ.
Rustom 2 (Tapas) is a very old design by Dr. Rustom Damania.
Although, both of these were meant for ISR (unarmed roles) only, Rustom 1 has been seen with two Helinas.
AURA/IUSAV/Ghatak is a stealth UCAV in development with ADA (with very limited funding).
Now some layman analysis:
1. I have always struggled with ADE's capability to design state-of-art UAVs. For example, the Hermes 900 weighs half as much as the Tapas, is half as powerful, but can carry the same payload for roughly the same duration. Another example, Hermes 450 weighs almost the same as Panchi, but carries 100 kg more payload and can stay aloft for 20 hours. I don't think that materials is the problem. Nishant/Panchi uses the best in class materials. I think the airframes are over designed, and the desi LRUs are much more heavier. Weight gain is additive: 350 kg of extra airframe will double the overall weight: more fuel, more wings, more engine, sturdier LGs.
2. The airframe looks simple, and I mean this as compliment. I am pretty sure there is a reason for the eyesore of an engine-cum-MLG fairing. Most probably, it is just an universal fairing till they finalize the engine. Otherwise they look circa 1920. However, I have a feeling they will change.
3. Two engines is not a bad thing. In the last year alone, we have lost a few large UAVs to engine failure. These UAVs are expensive, and can do some damage at the crash site.
4. The longest road to cover is actually the transmission range.
All in all, I think ADE has been very slow as an UAV designer in the past two decades:
1. I think that Tapas is double engine because this is how Dr. Damania designed it two decades ago.
2. Nishant had size limitations and sturdiness requirements owing to its mode of launch and recovery. But none of these exist for Panchi. Hence I expected them to go for elongated fuselage and much longer wings. Panchi has slightly longer wings, more payload and fuel capacity, and is powered by an uprated 65hp (Wankel engine from NAL). However, its specs will not get anywhere near the Hermes 450.
3. Lakhsya does not always work and many a times Marichs have to be used instead.
4. I have no idea what happened to Abhyas.
The private sector is close on the heels of ADE with collaboration with international partners. ADE probably has another 5 years at max as an UAV designer if it doesn't pull its socks up.